Intermittent/Random Wrench Light

[Vertex]

I think at some other time or in another thread I posted something about this, however, I don't believe anyone had any good thoughts that they'd had with theirs or ideas.

Just checking in to see if anyone has had a completely random/intermittent wrench light that, for me, only comes on at vehicle start up when it does come on. Other things I've noticed is when it is going to come on I know right away before the cluster cycles completely because the car almost sounds like it is going to stall out right after start up like it is stumbling or getting to much fuel. If I shut the car off and let it sit for roughly 2-3 minutes and fire it up again, so far, the light has gone out each time.

When I brought it in to the dealer I think it was only a couple days prior when the light had come on and the only codes in there were lost communication with the PCM ( I do not recall the code and do not have the paperwork handy). I asked if they could do a PCM update while they had it just to see if that would help since it did not seem/sound like a throttle body issue and I've still experienced it at least once since then.

Anybody else experience this same thing that I have? If so what work was performed to remedy the issue?

Forgot to note, this is on an S550 21 Mach 1

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[K4fxd]

The only way we can help is for you to read and post the code when the light comes on.

 

[Vertex]

The only way we can help is for you to read and post the code when the light comes on.

Being as I don't have a code reader/scan tool and the only code like I said was lost communication with the PCM and with how intermittent it is that will be unlikely. It is also parked for winter now.

Just been having this and a problem with the 4-5 upshift which is also intermittent and starting to turn me off to the car even though I've got 10 years of warranty on it.

 

[K4fxd]

Buy a cheap code reader. Unfortunately without a valid code no one can figure it out.

Lost comms is a common code and is nothing to worry about.

 

[Vertex]

Buy a cheap code reader. Unfortunately without a valid code no one can figure it out.

Lost comms is a common code and is nothing to worry about.

The only problem is when/if something does decide to completely fail I don't want to be stuck somewhere with a car that doesn't move. For now yes, it isn't a huge concern because I've figured out a way to get it to clear itself after just letting it sit a couple minutes after the incident occurs, however, if I'm on a longer road trip or something and it happens and the car is running like complete trash because I did run over to a gas station when it came on one of the time and the throttle was all over the place, that is when it will be a larger concern hence why I was checking to see if anyone else had experienced this with their car or not.

 

[MarkM]

The only problem is when/if something does decide to completely fail I don't want to be stuck somewhere with a car that doesn't move. For now yes, it isn't a huge concern because I've figured out a way to get it to clear itself after just letting it sit a couple minutes after the incident occurs, however, if I'm on a longer road trip or something and it happens and the car is running like complete trash because I did run over to a gas station when it came on one of the time and the throttle was all over the place, that is when it will be a larger concern hence why I was checking to see if anyone else had experienced this with their car or not.

Yes, I get the wrench symbol, mines connected to a P166A code, as above, the wrench is a generic something’s not right symbol, without reading the code it would just be guessing one of a hundred plus things it could be.

 

[raydog1]

I had the orange wrench pop up in rush-hour traffic around 2500 miles. Car also went into limp mode. I stopped at a local garage, but it came out of limp mode after restarting, so I decided to just go home and take it to the dealer the next day. The light went away the following morning and the dealer said they couldn't explain it and just "reset the ECU." 40,000 miles later... I haven't had the problem since then.

 

[Vertex]

I had the orange wrench pop up in rush-hour traffic around 2500 miles. Car also went into limp mode. I stopped at a local garage, but it came out of limp mode after restarting, so I decided to just go home and take it to the dealer the next day. The light went away the following morning and the dealer said they couldn't explain it and just "reset the ECU." 40,000 miles later... I haven't had the problem since then.

I wish I could say the same with mine after the ECM update. I've still had it come on again after getting the update done. Before getting it flashed I had it come on probably 3 or 4 times but it was never when driving the car just at start-up after it had been driven. I've never had it come on from a cold start.

 

[MiamiGT350]

A friend's throttle body had some bad electronics in it and his car behaved this way.

Of note, we would not find any error codes. This went on for weeks where the car would be completely fine, then just stumble and throw wrench.

Finally, one random day it happened and we already had a scanner connected and were able to get a throttle body position/range error.

I would just get a code scanner and connect it to the car before starting. If the issue occurs, quickly scan and you should find your issue/answer.

 

[Vertex]

A friend's throttle body had some bad electronics in it and his car behaved this way.

Of note, we would not find any error codes. This went on for weeks where the car would be completely fine, then just stumble and throw wrench.

Finally, one random day it happened and we already had a scanner connected and were able to get a throttle body position/range error.

I would just get a code scanner and connect it to the car before starting. If the issue occurs, quickly scan and you should find your issue/answer.

Do you know if the code that popped up or left in history was lost communication by chance or never had it checked prior to figuring out what the problem was?

 

[MiamiGT350]

Do you know if the code that popped up or left in history was lost communication by chance or never had it checked prior to figuring out what the problem was?

The specific error code was related to throttle position, and nothing to do with "lost communication."

A lost connection error is between two modules, so without the error code, you're only giving us half the information. So the PCM would be one side, and you'll need to let us know what the other module was. I have seen these happen on rough starts and sometimes when the car is on a battery tender.

Personal opinion: This error may be a result of a rough start, and more likely a symptom than a cause.

Try to get an error code...

 

[SheepDog]

I think at some other time or in another thread I posted something about this, however, I don't believe anyone had any good thoughts that they'd had with theirs or ideas.

Just checking in to see if anyone has had a completely random/intermittent wrench light that, for me, only comes on at vehicle start up when it does come on. Other things I've noticed is when it is going to come on I know right away before the cluster cycles completely because the car almost sounds like it is going to stall out right after start up like it is stumbling or getting to much fuel. If I shut the car off and let it sit for roughly 2-3 minutes and fire it up again, so far, the light has gone out each time.

When I brought it in to the dealer I think it was only a couple days prior when the light had come on and the only codes in there were lost communication with the PCM ( I do not recall the code and do not have the paperwork handy). I asked if they could do a PCM update while they had it just to see if that would help since it did not seem/sound like a throttle body issue and I've still experienced it at least once since then.

Anybody else experience this same thing that I have? If so what work was performed to remedy the issue?

Forgot to note, this is on an S550 21 Mach 1

Have you tested the battery? Are the battery terminals nice and tight?

 

[Vertex]

Have you tested the battery? Are the battery terminals nice and tight?

Yes they're good and actually just hooked up the tender to it last night. I know those connections are good and not a problem. Car never skips a beat and cranks perfect when I start it, it just starts to stumble when I know the wrench light is about to come on.

 

[SheepDog]

Yes they're good and actually just hooked up the tender to it last night. I know those connections are good and not a problem. Car never skips a beat and cranks perfect when I start it, it just starts to stumble when I know the wrench light is about to come on.

Seems like a connection or ground issue to me. How mechanically enclined/automotive savvy are you?

I'd be poking around in the engine bay, looking for loose grounds, connectors that aren't fully seated (especially at the PCM) and looking for chaffed wires.

Do you have any mods on the car? Ever had any services performed other than routine maintenance?

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