Code P1610 and Code P1612 + brain picking

[sk47]

Hello; Started this in the off topic area because it is not about a Mustang. I do figure there are some sharp minds here from the posts and threads I have read. The thread is going to be about an opportunity for me to learn more about the anti-theft system on my Nissan Sentra. May be some of the sharp minds on here can help.

I bought a 2001 Nissan Sentra SE new. It has the 2.0 liter engine. That car was up until a few days ago very reliable. I backed it out of my basement garage and moved it a short distance then shut it off so I could work on my truck and not have it blocked in in case I needed to go get parts.
A few hours later the Sentra will not start. I get out the OBDII code reader and hook it up. No stored codes at all. The car has never thrown a code and had never failed to start before.

The code it has are pending codes P1610 and P1612. Both turn out to be about the NATS system. That system is the anti-theft system. I guess some how that system was triggered. I was using one of the factory keys that came new with the car, not a replacement. In fact I have tried all three of the keys that came with the car.

The best guess I have so far is that the battery was too weak. It was the battery that came in the car in 2001, so around 18+ years old. It had been still starting the car even tho it did not spin so fast sometimes. I am guessing the low battery may have been a cause, but only a guess.

I put a new battery in today but this did not help other than it cranks faster. I looked up the NATS system and found a few things to try. One was to turn the key on without cranking for ten seconds, then off for five seconds, then on again and off again for three times. Did not work but that was with the old battery and I have not tried it with the new battery. ( will have to try that way)

I talked to a local mechanic. If it is the NATS system he cannot fix it. He suggested I try to lock and unlock the doors with the key and the key fob. I did so but did not help.

I am sure there is no spark but not so sure about the fuel pump. There is not a test valve on the fuel injection rail so I cannot attach my test gauge.

I did learn one thing today. That same mechanic suggested I set my OBDII reader to live data at the RPM setting and crank the engine. If it shows RPM while cranking then the crankshaft position sensor is good. If no RPM while cranking then that sensor is faulty. I had 750 RPM when cranking. That sensor was going to be the first thing replaced but now will not.

I called the Nissan dealership closest to me, about 40 miles away. They can check and fix it for $186 but I will have to have it towed. They gave me a local locksmith number. It seems that some locksmiths can work on these anti theft systems. He is to come by later today. On the phone his suspicion is about the sensor coil where the key is inserted may be bad. That is all so far.

I get that some will not wish to join in a thread about a Nissan. My guess is something may be learned about these anti-theft in general and ask for your patience. Thanks in advance to any who choose to participate.

Sponsored

 

[sk47]

Hello; Had a local lock smith come by. He says the problem is not the anti-theft because when he cranked the engine the red indicator light did not flash. Also a symbol did not appear on the dash.
He was suspicious that a bad fuel pump might also stop the spark. Looked at the Haynes manual and thinks my setup will keep a spark even with a bad fuel pump. So I am back to looking for something that kills the spark at the plugs.
Back to a search for something that kills the spark.

He gave me a neat thing to do. Say I question a part such as the crankshaft sensor. Take the old sensor out and go to a parts store. If they have a new part in stock check the ohms of the new part and compare to the old part. Worth a try I guess.

 

[cmxPPL219]

I was in the Nissan world (2005 Altima SE-R 6spd) prior to my Mustang, so I'll bite.

Can't say I can point you to an ultimate fix, but I will say that it's strange that you are getting the NATS / NVIS Immobilizer codes, but the red light does not remain on while cranking.

Sometimes, the immobilizer ring device (in the steering column,m where you insert the key into the ignition, which senses the chip in the matching key, allowing the vehicle to start) can become faulty, requiring reprogramming, etc. But, the light should flash while ignition / crank, so not sure what gives here.

If you do end up fixing it with a crank sensor, make sure you get a Nissan part to be safe. I assume you're replacing an original, and Nissan has updated part #s for Crank and Cam sensors over the years.

Hope you can find out what this issue is, and not require a tow. Keep us updated.

By the way, shocked that your original battery lasted almost 2 decades. The oem ford batteries in these Mustangs are barely making it to 3.

 

[sk47]

I was in the Nissan world (2005 Altima SE-R 6spd) prior to my Mustang, so I'll bite.

Can't say I can point you to an ultimate fix, but I will say that it's strange that you are getting the NATS / NVIS Immobilizer codes, but the red light does not remain on while cranking.

Sometimes, the immobilizer ring device (in the steering column,m where you insert the key into the ignition, which senses the chip in the matching key, allowing the vehicle to start) can become faulty, requiring reprogramming, etc. But, the light should flash while ignition / crank, so not sure what gives here.

If you do end up fixing it with a crank sensor, make sure you get a Nissan part to be safe. I assume you're replacing an original, and Nissan has updated part #s for Crank and Cam sensors over the years.

Hope you can find out what this issue is, and not require a tow. Keep us updated.

Hello; On the phone the locksmith talked about that very ring device in the steering column. He called it a coil. When he found the location of the little red light and cranked the engine he said the problem is not that. Best I can recall the light did stay on, but he seemed to think it should flash rapidly. Also I think he expected some sort of symbol to show up on the dash. I will watch that indicator light next time I fool with the car.

My plan has been to get a Mustang GT with a manual and to keep the Sentra as the choir car. Almost had a GT twice but the deals fell thru. First time I found a all white GT about 100 miles away. Worked out a good deal on the phone and drove up to get the car. The dealer had put what he called a wrap on the roof, fenders and spoiler. It was a base model GT and I guess the wrap was to make it look more like a more expensive model. I did not know about wraps and how to remove them. Dealer would not remove the wrap. On his website the pictures were of an all white car.
The other was a good deal on a left over (previous model year) GT in Ohio. Again over the phone we got to the number I wanted. I had the check with me from my bank as the dealer had asked for a cash purchase. They wanted my SS # and I would not give it out saying I was not going to finance. Found out later Ohio DMV requires this. May have been just as well since i was depending on a friend to drive me up to get my Sentra. After I found out it was not a dealer thing on the SS# I was going to go back. My friend agreed to drive me up but failed to show up twice so I lost the car.

Thanks for the reply. So far I am striking out. I still am a bit confused about the NATS codes and the locksmith being so sure that is not the issue.

 

[cmxPPL219]

Hello; On the phone the locksmith talked about that very ring device in the steering column. He called it a coil. When he found the location of the little red light and cranked the engine he said the problem is not that. Best I can recall the light did stay on, but he seemed to think it should flash rapidly. Also I think he expected some sort of symbol to show up on the dash. I will watch that indicator light next time I fool with the car.

My plan has been to get a Mustang GT with a manual and to keep the Sentra as the choir car. Almost had a GT twice but the deals fell thru. First time I found a all white GT about 100 miles away. Worked out a good deal on the phone and drove up to get the car. The dealer had put what he called a wrap on the roof, fenders and spoiler. It was a base model GT and I guess the wrap was to make it look more like a more expensive model. I did not know about wraps and how to remove them. Dealer would not remove the wrap. On his website the pictures were of an all white car.
The other was a good deal on a left over (previous model year) GT in Ohio. Again over the phone we got to the number I wanted. I had the check with me from my bank as the dealer had asked for a cash purchase. They wanted my SS # and I would not give it out saying I was not going to finance. Found out later Ohio DMV requires this. May have been just as well since i was depending on a friend to drive me up to get my Sentra. After I found out it was not a dealer thing on the SS# I was going to go back. My friend agreed to drive me up but failed to show up twice so I lost the car.

Thanks for the reply. So far I am striking out. I still am a bit confused about the NATS codes and the locksmith being so sure that is not the issue.

Sorry to hear about those leads on the Mustang falling through. In the first situation, no idea what the heck that dealer was up to and those wrap shnenigians. In the second, it's also disappointing that your friend flaked out and didn't show. Hope that person isn't your friend anymore. Maybe third time is a charm.

Anyway, back to the Sentra, this supposedly what should happen:

Security indicator light

The security indicator light A indicates the status of the NISSAN Vehicle Immobilizer System.
The light blinks after the ignition switch was in the ACC, OFF and LOCK position. This function indicates the security systems equipped on the vehicle are operational.
If the NISSAN Vehicle Immobilizer System is malfunctioning, this light will remain on while the ignition switch is in the ON position.
If the light still remains on and/or the engine will not start, see a NISSAN dealer for NISSAN Vehicle Immobilizer System service as soon as possible. Please bring all registered keys that you have when visiting a NISSAN dealer for service.

See, I would want a second opinion just to be sure, regarding the locksmith being so sure it's not the immobilizer ring in the column, or any other immobilizer component.

With OBDII code and diagnostics, a code and it's description doesn't necessarily indicate the source of the problem - often, it is just a starting point for diagnostics, and something totally irrelevant can throw a given CEL. However, in this case, NATS codes are really specific to Nissan, and you have no other codes accompanying the NATS codes, so I would be surprised to see that it wasn't anything to do with the immobilizer system.

Like, for example, a crankshaft position sensor problem usually doesn't usually throw a NATS code. Again, not saying for sure you do not have an immobilizer issue, but depending on how much patience and time you have to solve for this, it could be worth a second opinion or, ultimately, a trip to the dealer.

Otherwise, a full diagnostic just to be sure (crank, fuel pressure, spark, etc.) would be a good idea. Checking for any fuses that relate to the NATs system. Have you worked on the car recently for another component? All harnesses plugged in, etc?

Hopefully this helps as well, keep us updated.

 

[sk47]

Security indicator light

Hello; My car is a 2001 model and has a red light which is on the dash close to the windshield on the passenger side. I have noted that when the car is sitting the red light will come on once in a while. Maybe every ten to fifteen seconds. I went back and cranked the engine last night and watched the light, it stayed off when cranking. I guess that is what the locksmith was looking for.
There is not now nor never has been the image you posted of a car outline with a key inside on my cars dash. Not sure why unless being nearly 20 years old the image is a newer feature. Good post tho.

See, I would want a second opinion just to be sure, regarding the locksmith being so sure it's not the immobilizer ring in the column, or any other immobilizer component.

Hello; This is indeed the dilemma right now. The car has code for the NATS and the locksmith says such is not the issue.

NATS codes are really specific to Nissan, and you have no other codes accompanying the NATS codes, so I would be surprised to see that it wasn't anything to do with the immobilizer system.

Hello; Agreed, I can waste a lot of time and money throwing parts and if it is the NATS still will not fix the car.

Hopefully this helps as well, keep us updated.

Hello; About my friend. Over the last few years I have used my pickup to help him with various things. For example when his wife's father died we used my truck to haul loads of items to his daughters, one over 50 miles away. I never took gas money as well. I repaired his lawn mowers, vacuum cleaner and dishwasher as well.
After the first trip to Ohio fell thru over the SS#, the plan changed to he would drive me up in his car so I could pick up the GT. It is about a four hour trip so I guess he actually did not wish to go. I stopped by his house on a Sunday or Monday to ask for his help. He says he can go the following Wednesday, but never showed up. That happened one more time so I took the hint.
Shame is a few months later he hit me up to take some furniture to Knoxville TN about 50 miles away. I took him but did ask for gas money that time. Could be the virus but he has not asked for such favors lately.

Thanks for the reply. I knew there are some sharp members on this forum. I have worked on my own cars and the cars of others for decades. I am not certified or such , but am self trained. I guess that means I have made enough mistakes to have learned from them. My big problem is finding information in enough detail so the various components can be checked out before just replacing parts and hoping for the best. I have a Haynes manual but for many things it tells me to take the car to a certified dealer or shop.

 

[sk47]

Hello; Tried another thing but it did not work. Read about leaving the key in the on position (dash lights lit but no crank) for a while, maybe ten minutes, then crank.

Made more observations about the red security light of the immobilizer system. My manual states it should blink every three seconds, now it blinks every thirty seconds or so.
If I turn the key directly over to crank the red security light stays off.
However if I turn the key on (dash light lit ) and wait a few seconds the red security light stays on and stays on when I turn it over to crank.

One other observation. The two remote fobs will lock and unlock the doors but now will not open the trunk.

 

[cmxPPL219]

However if I turn the key on (dash light lit ) and wait a few seconds the red security light stays on and stays on when I turn it over to crank.

This observation right here, would almost certainly indicate an immobilizer issue, based on what the Nissan info is suggesting, that I pasted earlier:
"If the NISSAN Vehicle Immobilizer System is malfunctioning, this light will remain on while the ignition switch is in the ON position.
If the light still remains on and/or the engine will not start, see a NISSAN dealer for NISSAN Vehicle Immobilizer System service as soon as possible. Please bring all registered keys that you have when visiting a NISSAN dealer for service."

Just to be sure, I would want a second opinion, to see if this opinion aligns with the first locksmith.
Or, you could bite the bullet and tow it to Nissan. They should be able to just tell you what it is, immobilizer issues are not that uncommon on the older vehicles.

 

[sk47]

This observation right here, would almost certainly indicate an immobilizer issue, based on what the Nissan info is suggesting, that I pasted earlier:
"If the NISSAN Vehicle Immobilizer System is malfunctioning, this light will remain on while the ignition switch is in the ON position.
If the light still remains on and/or the engine will not start, see a NISSAN dealer for NISSAN Vehicle Immobilizer System service as soon as possible. Please bring all registered keys that you have when visiting a NISSAN dealer for service."

Just to be sure, I would want a second opinion, to see if this opinion aligns with the first locksmith.
Or, you could bite the bullet and tow it to Nissan. They should be able to just tell you what it is, immobilizer issues are not that uncommon on the older vehicles.

Hello; Your take matches mine so far. In some of the things I find when searching there is a bit of what to expect that does not match what is happening with my car. I think I will touch base with another Nissan shop and ask about just what I should be looking for with that red security light.
I figure the car will have to be towed to a Nissan dealer at this point.

I did finally come to understand why I was not seeing the car outline with a key inside image. On my car the red indicator is located on the dash close to the windshield, but apparently is the same sort of light.

If the NISSAN Vehicle Immobilizer System is malfunctioning, this light will remain on while the ignition switch is in the ON position.

Hello; This bit seems to cover my situation.

Thanks again

 

[sk47]

Hello; Thought I would write down some of what I have found since yesterday. Still cannot start car.
A positive thing is I have found a site which has digital copies of the factory repair manual for many Nissan models including my own. I have been pouring over this for the last few hours. It will of use I think. I now have a listing for the ohms value of resistance for many sensors and other control systems. This should help.

I decided to phone the locksmith again to ask if my discovery about the red immobilizer was significant. Indeed it may be but he is still at a loss. First time, a couple of days ago, he had just turned the key on and directly over to the crank position. Today he saw that the light came on steady after about five seconds and stayed on when cranking. So he got out some test equipment this trip. However he could not get readings for some reason and was stumped. At least he has only charged me $20 for two visits. We did confirm there is for sure no spark at the plugs. He also said he could hear the fuel pump ramp up. ( My hearing is not so good anymore so this was good)
(NOTE- I did find a method for checking if the fuel pump is working in the digital manual. The fuel lines are some sort of plastic so if you squeeze the fuel line in the engine compartment with your fingers it says you should feel the pump vibration pulses for about five seconds.)

I also found in the digital manual about the crankshaft sensor test using an ohm meter. Mt crank sensor is within specs so must be good. ( It also threw RPM's in my OBDII live data test)

Anyway I have some new ways to test some items and will do so tomorrow.

 

[cmxPPL219]

Thanks for the update - Let's see what happens. It just doesn't sound like it was a crank sensor issue.

Will be really interested to see what this ends up being.

 

[sk47]

Hello; Thought I would update the progress so far. Still no start. I have been doing checks of things such as looking at the wires and connectors and cleaning grounds. Found a Factory service manual online and have printed out a lot of pages. Been doing some checks I can.

I have the plastic covers off from around the steering column exposing the key mechanism. There is a part of the antitheft system called the IMMU. It is a coil of wire which acts as an antenna and is attached to a small box which apparently has electronic bits inside. My ignition key has a chip and when the key is turned on the antenna coil somehow generates a signal to the chip in the key and reads a code in the key. I bought a tool which is supposed to read that signal.

The tool is an ECU Induction Coil Signal Detection Card, Model: AKS-CARD-ECU from American Key Supply. It is a small card with a hole in the middle surrounded by a circle of wires and a small light bulb. The idea is to hold the card where the key inserts and turn the key on. The signal is supposed to light up the card's small light.
So far I cannot get it to light up on the Sentra. It also does not light up on some other cars it has been tried on. A Honda civic. A Toyota. A ford pickup and a Chevy pickup. I guess it could be those other vehicles do not have the same sort of system.
I tried to test the card tool by holding it close to an electric motor when I turned it on. Got a weak (dim)flash that way. So I tried the Sentra again with little light around, but no luck.

What follows is the notes I have been keeping for when I finally give up and have it towed to a dealer.

- Sudden no start with no prior problems or warnings.

- Only two codes = pending codes P1610 and P1612. No old codes at all

- Had weak battery at time of first no start. Have replaced with new battery.

- Was using the same factory key that had been in use for many years and came with the car new.

- Red security light will come on and stay on with key on. ( see notes below for details)

- Red security light now flashes every thirty seconds now with key off. Manual says it should flash about at 3 seconds

- If I lock the driver’s door with a key having the windows up, hood and trunk closed the red security light comes on for thirty seconds then goes off as it is supposed to by the manual. After that it flashes once apporximately every 30 seconds or so.

Have a will crank but no start problem with 2001 Sentra SE with the 2.0 liter engine. Miles = 133 K. Bought the car new. On December 10, 2020 it would not start for the first time ever. Crank but no start. Had a weak battery in it at the time. It was a mild day in the 50’s F. I started the car and moved it from the basement garage to just behind my home. It started and ran fine as was normal. I did not let it fully warm up before I shut it off. A few hours later it would not start using the same factory key (valet key) that came with the car when new. First time I tried to start it, it cranked only. Turned the key off and tried again and it fired on maybe two or three cylinders for a very brief second. Tried a third time and again only a very brief firing on a couple of cylinders. Since then only will crank with no sign of firing.

-Used an OBDII code reader. Found no old codes. Found two pending codes P1610 (IMMU or ECM is malfunctioning) and P1612 (communication impossible between ECM and IMMU). Looked these codes up and find they are for the immobilizer system. The code reader called it the NATS system. My owner’s manual calls it the NVIS system. For what it may be worth the car has never had a check engine light before or even now.

Summary of what I have tried and found so far.

- Installed a new battery. The battery which was in the car at the time of the no start was weak and old.

- Pretty sure there is no spark. Tested with a timing light and pulled a sparkplug and got no spark.

- Not sure about the fuel pump as there in no fuel rail valve to hook my test gauge onto. I cannot for sure hear the fuel pump ramp up. One person, a locksmith, says he heard the pump. I took the back seat out and the floor cover off above the tank. I can touch the lines that exit the pump while I turn the key on, I have felt a vibration for a few seconds.

- Was using one of the three factory keys that came with the car, the valet key, when the no start happened. The same key I have been using for years.

=Tried with key on (but not all the way to crank) for five to ten seconds, then key off for five to ten seconds and repeated two times and again three times with both the old charged battery and the new battery. No luck.

Tried all three keys.

=Undid the battery for an hour the first time and for two days later when I waited to get a new battery, no luck with that either.

=Tried locking and unlocking the doors both with all three keys and both remote key fobs. NOTE- the key fobs will work the door locks properly. Only one fob will open the trunk sometimes, but not all the time, and it has to be used inside the car when it does open the trunk. Not sure if that is a clue but it is a new symptom, the key fob had been opening the trunk just a few days before. The trunk will open with the button the dash and with a black key.

- Had only an ignition key with one of the remote fobs on the key ring. My owner’s manual mentions interference but I was using the same factory key + fob that had started the car about four hours before the no start and for over 18 years before that.

-Tried leaving a key in the ignition for many hours in the off position and also for maybe ten minutes in the on position (dash lights lit up)





-a local LOCKSMITH has come by twice. First time he seemed to think the immobilizer system is not at fault by looking at the little red security on the dash when he cranked the engine and the light did not come on. He turned the key on and straight over to crank watching the red security light on the dash. It will stay off if you do it that way. After some reading found that with the key on the red security light is supposed to come on steady if there is a problem with the IMMU/antitheft system. What I observe about that red light follows.

= The red light blinks once about every thirty (30) seconds now. Owner’s manual states this indicator light should blink every three (3) seconds if the ignition is in lock, off or ACC position and this sounds correct about the way it blinked before.

= If, as the locksmith did the first time, I turn the key from off directly to the crank position the red light stays off if it was already off while the engine cranks.

= If I turn the key to the on position (dash lights are on but not yet to crank) and wait about five seconds the indicator red security light comes on and stays on. If I turn the key further to the crank position the engine cranks and the red indicator light stays on constantly while cranking.

Locksmith came back and he observed the same thing. He tried some equipment this time. A device he held near the key in the ignition and a device he plugged into the OBDII port. Apparently he did not get readings expected and maybe if I heard him correctly no readings at all.

I have since learned there is a coil which surrounds the key, the IMMU I think, and it gets energized when the key is turned on and reads the chip in the key for a code. I did not know enough at the time to ask but am now guessing the locksmith was looking for the coil in the IMMU to give a reading. He left telling me he is not sure what is going on. He suggested the crankshaft position sensor may be at fault.



- Did two checks of the crankshaft position sensor. One check with the OBDII reader set it in live data mode at RPM. When I crank the engine over it reads some RPM's 350 RPM's. I think this indicates the crankshaft position sensor is working? I also pulled the crank sensor and checked the ohms. It is within the range of 166 to 204 ohms at 68 degrees F, I found in the Factory Service Manual page EC -1671

- Located and cleaned several grounds.

- Removed and checked spark plugs, distributor cap and rotor. These are not new but all have been replaced in the last 30K miles or so.

- Discovered the ignition coils and cam sensor are part of the distributor. Found some tests in the Nissan factory service manual found online and performed those I could. Did the following.

= from page EC-1617 Cleaned two grounds. Did check power supply test

= from page EC-1617 check for voltage between distributor harness connector terminal 5 and ground. Had voltage.

= from page EC-1904 checked ohms on ignition coil harness connector. Had 0.6 ohms. Manual called for0.8 ohms.

= from page EC-1904 checked secondary terminal on distributor head (secondary coil) showed 14.8K ohms. Manual calls for around 16K ohms.

= from page EC-1904 checked power transistor. Between terminal 2 and 8 got 41.6 K ohms OK

= from page EC-1904 checked distributor cap. Had 6K ohms manual showed 4K to 8K ohms.

- Checked fuses. Pretty sure all fuses are good, not sure about relays, looked at fuseable links.

= starter signal fuse (10 A) has no voltage with key off and no voltage with key on but not to crank. I cannot be in position to check when cranking.

- NVIS IMMU things I can check

= from page EL-310 NVIS IMMU connector; check power supply circuit. With key off terminal 8 has battery voltage

= from page EL-311 NVIS IMMU connector; check IGN SW. ON signal. Key on =OK

= from page EL-311 NVIS IMMU connector 4 for continuity = OK



My dilemma at this point is the conflict between the NATS codes the car throws and the opinion of the locksmith. I can start to replace parts but understand that if the immobilizer system has cut things off, then this will be pointless.







From Forum source - If the keys are all doing the same thing then chances are it's a dead IMMU. There's no good way to test them out of the car, it's an inductive RFID system. Generally the older ECM's give you 7 cranks before they go lockout and then 7 more before they commit suicide. Once you get the IMMU fixed, if the lockout code won't clear then the ECM is done.

 

[sk47]

Hello; A shorter question. About the crankshaft position sensor. I saw a video where the tach on the dash ought to show some RPM's when cranking even if the engine will not start. I tried to watch my tach today as the engine cranked. I could not see any movement of the needle. I do not know if this means anything, so am asking.

To recap, I pulled the crank sensor and checked for resistance with an OHM meter. It was within specs. With my OBDII I saw RPM's when cranking with the OBDII in live data mode and set at RPM's. I have been taking these two outcomes to indicate the crank sensor is still good so have not replaced it yet. Any thoughts???

 

[cmxPPL219]

Hello; Thought I would update the progress so far. Still no start. I have been doing checks of things such as looking at the wires and connectors and cleaning grounds. Found a Factory service manual online and have printed out a lot of pages. Been doing some checks I can.

I have the plastic covers off from around the steering column exposing the key mechanism. There is a part of the antitheft system called the IMMU. It is a coil of wire which acts as an antenna and is attached to a small box which apparently has electronic bits inside. My ignition key has a chip and when the key is turned on the antenna coil somehow generates a signal to the chip in the key and reads a code in the key. I bought a tool which is supposed to read that signal.

The tool is an ECU Induction Coil Signal Detection Card, Model: AKS-CARD-ECU from American Key Supply. It is a small card with a hole in the middle surrounded by a circle of wires and a small light bulb. The idea is to hold the card where the key inserts and turn the key on. The signal is supposed to light up the card's small light.
So far I cannot get it to light up on the Sentra. It also does not light up on some other cars it has been tried on. A Honda civic. A Toyota. A ford pickup and a Chevy pickup. I guess it could be those other vehicles do not have the same sort of system.
I tried to test the card tool by holding it close to an electric motor when I turned it on. Got a weak (dim)flash that way. So I tried the Sentra again with little light around, but no luck.

What follows is the notes I have been keeping for when I finally give up and have it towed to a dealer.

- Sudden no start with no prior problems or warnings.

- Only two codes = pending codes P1610 and P1612. No old codes at all

- Had weak battery at time of first no start. Have replaced with new battery.

- Was using the same factory key that had been in use for many years and came with the car new.

- Red security light will come on and stay on with key on. ( see notes below for details)

- Red security light now flashes every thirty seconds now with key off. Manual says it should flash about at 3 seconds

- If I lock the driver’s door with a key having the windows up, hood and trunk closed the red security light comes on for thirty seconds then goes off as it is supposed to by the manual. After that it flashes once apporximately every 30 seconds or so.

Have a will crank but no start problem with 2001 Sentra SE with the 2.0 liter engine. Miles = 133 K. Bought the car new. On December 10, 2020 it would not start for the first time ever. Crank but no start. Had a weak battery in it at the time. It was a mild day in the 50’s F. I started the car and moved it from the basement garage to just behind my home. It started and ran fine as was normal. I did not let it fully warm up before I shut it off. A few hours later it would not start using the same factory key (valet key) that came with the car when new. First time I tried to start it, it cranked only. Turned the key off and tried again and it fired on maybe two or three cylinders for a very brief second. Tried a third time and again only a very brief firing on a couple of cylinders. Since then only will crank with no sign of firing.

-Used an OBDII code reader. Found no old codes. Found two pending codes P1610 (IMMU or ECM is malfunctioning) and P1612 (communication impossible between ECM and IMMU). Looked these codes up and find they are for the immobilizer system. The code reader called it the NATS system. My owner’s manual calls it the NVIS system. For what it may be worth the car has never had a check engine light before or even now.

Summary of what I have tried and found so far.

- Installed a new battery. The battery which was in the car at the time of the no start was weak and old.

- Pretty sure there is no spark. Tested with a timing light and pulled a sparkplug and got no spark.

- Not sure about the fuel pump as there in no fuel rail valve to hook my test gauge onto. I cannot for sure hear the fuel pump ramp up. One person, a locksmith, says he heard the pump. I took the back seat out and the floor cover off above the tank. I can touch the lines that exit the pump while I turn the key on, I have felt a vibration for a few seconds.

- Was using one of the three factory keys that came with the car, the valet key, when the no start happened. The same key I have been using for years.

=Tried with key on (but not all the way to crank) for five to ten seconds, then key off for five to ten seconds and repeated two times and again three times with both the old charged battery and the new battery. No luck.

Tried all three keys.

=Undid the battery for an hour the first time and for two days later when I waited to get a new battery, no luck with that either.

=Tried locking and unlocking the doors both with all three keys and both remote key fobs. NOTE- the key fobs will work the door locks properly. Only one fob will open the trunk sometimes, but not all the time, and it has to be used inside the car when it does open the trunk. Not sure if that is a clue but it is a new symptom, the key fob had been opening the trunk just a few days before. The trunk will open with the button the dash and with a black key.

- Had only an ignition key with one of the remote fobs on the key ring. My owner’s manual mentions interference but I was using the same factory key + fob that had started the car about four hours before the no start and for over 18 years before that.

-Tried leaving a key in the ignition for many hours in the off position and also for maybe ten minutes in the on position (dash lights lit up)





-a local LOCKSMITH has come by twice. First time he seemed to think the immobilizer system is not at fault by looking at the little red security on the dash when he cranked the engine and the light did not come on. He turned the key on and straight over to crank watching the red security light on the dash. It will stay off if you do it that way. After some reading found that with the key on the red security light is supposed to come on steady if there is a problem with the IMMU/antitheft system. What I observe about that red light follows.

= The red light blinks once about every thirty (30) seconds now. Owner’s manual states this indicator light should blink every three (3) seconds if the ignition is in lock, off or ACC position and this sounds correct about the way it blinked before.

= If, as the locksmith did the first time, I turn the key from off directly to the crank position the red light stays off if it was already off while the engine cranks.

= If I turn the key to the on position (dash lights are on but not yet to crank) and wait about five seconds the indicator red security light comes on and stays on. If I turn the key further to the crank position the engine cranks and the red indicator light stays on constantly while cranking.

Locksmith came back and he observed the same thing. He tried some equipment this time. A device he held near the key in the ignition and a device he plugged into the OBDII port. Apparently he did not get readings expected and maybe if I heard him correctly no readings at all.

I have since learned there is a coil which surrounds the key, the IMMU I think, and it gets energized when the key is turned on and reads the chip in the key for a code. I did not know enough at the time to ask but am now guessing the locksmith was looking for the coil in the IMMU to give a reading. He left telling me he is not sure what is going on. He suggested the crankshaft position sensor may be at fault.



- Did two checks of the crankshaft position sensor. One check with the OBDII reader set it in live data mode at RPM. When I crank the engine over it reads some RPM's 350 RPM's. I think this indicates the crankshaft position sensor is working? I also pulled the crank sensor and checked the ohms. It is within the range of 166 to 204 ohms at 68 degrees F, I found in the Factory Service Manual page EC -1671

- Located and cleaned several grounds.

- Removed and checked spark plugs, distributor cap and rotor. These are not new but all have been replaced in the last 30K miles or so.

- Discovered the ignition coils and cam sensor are part of the distributor. Found some tests in the Nissan factory service manual found online and performed those I could. Did the following.

= from page EC-1617 Cleaned two grounds. Did check power supply test

= from page EC-1617 check for voltage between distributor harness connector terminal 5 and ground. Had voltage.

= from page EC-1904 checked ohms on ignition coil harness connector. Had 0.6 ohms. Manual called for0.8 ohms.

= from page EC-1904 checked secondary terminal on distributor head (secondary coil) showed 14.8K ohms. Manual calls for around 16K ohms.

= from page EC-1904 checked power transistor. Between terminal 2 and 8 got 41.6 K ohms OK

= from page EC-1904 checked distributor cap. Had 6K ohms manual showed 4K to 8K ohms.

- Checked fuses. Pretty sure all fuses are good, not sure about relays, looked at fuseable links.

= starter signal fuse (10 A) has no voltage with key off and no voltage with key on but not to crank. I cannot be in position to check when cranking.

- NVIS IMMU things I can check

= from page EL-310 NVIS IMMU connector; check power supply circuit. With key off terminal 8 has battery voltage

= from page EL-311 NVIS IMMU connector; check IGN SW. ON signal. Key on =OK

= from page EL-311 NVIS IMMU connector 4 for continuity = OK



My dilemma at this point is the conflict between the NATS codes the car throws and the opinion of the locksmith. I can start to replace parts but understand that if the immobilizer system has cut things off, then this will be pointless.







From Forum source - If the keys are all doing the same thing then chances are it's a dead IMMU. There's no good way to test them out of the car, it's an inductive RFID system. Generally the older ECM's give you 7 cranks before they go lockout and then 7 more before they commit suicide. Once you get the IMMU fixed, if the lockout code won't clear then the ECM is done.

A lot of thorough self-diagnostics - that has helped in seeing what you've tried to do to solve this.

Again, I can't say for sure, but it seems to me that you do have some issue with the NATS/NVIS system, just from reading everything. But again, this is just from what I'm seeing - especially if the crank sensor tests fine.

The other thing that it could be, is the ECM itself - Because the NATS is built into the ECM, perhaps there is something corrupted in there? Who knows.

 

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Hello; A shorter question. About the crankshaft position sensor. I saw a video where the tach on the dash ought to show some RPM's when cranking even if the engine will not start. I tried to watch my tach today as the engine cranked. I could not see any movement of the needle. I do not know if this means anything, so am asking.

To recap, I pulled the crank sensor and checked for resistance with an OHM meter. It was within specs. With my OBDII I saw RPM's when cranking with the OBDII in live data mode and set at RPM's. I have been taking these two outcomes to indicate the crank sensor is still good so have not replaced it yet. Any thoughts???

Regarding seeing the Tach needle move upon crank, this doesn't seem to occur with a lot of relatively modern vehicles. Most of the time, a scan tool will have to be hooked up to see the live RPM data. I'm not sure if the 2001 Sentra should show the tach move upon crank attempt, but just some food for thought.

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