Hello All, I have a 1999 Mitsubishi Galant GTZ 3.0L and I have been preparing this vehicle for emissions testing. Recently the engine light came on and I had a friend run a diagnostic and found error code P0125, which is;

• Insufficient warm up time, Low engine coolant level
• Leaking or stuck open thermostat
• Faulty coolant temperature sensor

Ok I had the ECT sensor, thermostat housing, thermostat and thermostat switch replaced. My friend reset the computer and 3-4 days later the light came on again. I have until July 10th to complete my emissions but I'm stumped and don't know what to do? Can someone help me please...


Thank you...

 

So, was it the same code that came back? Did you fill up the coolant?

 

Hello jkean, Yes it was the same code P0125

 

Coolant is topped off..

 

Below are come more common problems that trigger the P0125 Code

• Defective Engine Thermostat - replaced
• Defective Engine Coolant Temperature Sensor - replaced
• Defective Intake Air Temperature Sensor - ?
• Defective Cooling System - ?
• Low Engine Coolant - filled
• Dirty Engine Coolant, causing incorrect Coolant Temperature Sensor readings -?
• Defective, always running Engine Cooling fan(s) - ?

Some other areas to check.

 

Thank you very much jkeaton, I will check the common problems you listed this weekend.

 

P0125....Insufficient Coolant Temperature for Closed Loop Fuel Control

 

Is your fan coming on to soon or on constantly even when cold with no a/c. If e fan is on too soon it could cause this problem as well. Oversized radiator? Have friend with scanner check you intake air temp reading and ambient temp as well. Keep us updated. What kind of t stat did you install?