I have a 2003 GMC Safari 4.3 liter service enginge light came on and stays on. I pulled codes and it has P0128 does anyone have the flow chart for that code? I was laid off and the shop closed I was working for and I don't have access to newer repair info at home.

Thank you
Pep

 

P0128 Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

Theres a sticky at the top of the General Tech that has most all of the obd codes.

 

Yes I know what the code definition is I'm looking for the repair flow chart.


Thanks

 

Replace the t-stat. It fixes it every time. A bad temp sensor could be the cause also but I have yet to replace one.

 

Thanks for the quick reply I'll give it a try in the morning.

Pep