350R throwing DTC code P0128

[AgSurfer]

The other day (magically after I left the dealer for an oil change and brake flush), my 2020 GT350R (4k miles) is showing check engine light. Used my OBD II scanner, and it is showing DTC code P0128. Relates to coolant thermostat / coolant temperature.

I believe other 350 / 350R owners have experienced this, some more regularly than others. What is the likely fix:

1. Repaid thermostat?
2. Replace thermostat?
3. Repair / replace housing?

I have - and will again - mention to the dealer this is not uncommon for the 350s / 350Rs. It will be under warranty.

Thanks for the input.

Sponsored

 

[Postal Bob]

When the light came on, what was the engine temp? Was it even registering?
Could also be the engine coolant sensor malfuntioning.

 

[bauern]

Visual check

Gasoline Engines PCED

• P0128 indicates the engine coolant temperature has not achieved the required engine operation temperature level, since start-up within a specified amount of time.
• Check the cooling system for:
  • correct coolant level
  • internal or external coolant leaks
  • blockage of the radiator
  • cooling fan operation

After this, it goes to the CHT sensor/wire harness check list.

 

[AgSurfer]

When the light came on, what was the engine temp? Was it even registering?
Could also be the engine coolant sensor malfuntioning.

light came on upon start. Light remained on for a 15 minute drive home.

Have not started the car in a week. I will start and let it run for a bit this weekend and see what happens. If the temperature rises enough this weekend, I will take it for a light drive and see if anything changes.

I went ahead and had the dealer order the thermostat.

 

[11GT50]

It's most likely the thermostat. I've had several of them stick open enough that the car won't get up to minimum temperature and set that code. It's an easy job to replace it.

Sponsored