For Shop Owners

P0125 TOYOTA - Insufficient Coolant Temperature for Closed Loop Fuel Control

Repair Importance Level: 3/3
Repair Difficulty Level: 2/3 What does this mean?

Possible causes

  • Low engine coolant level
  • Leaking or stuck open thermostat
  • Faulty Engine Coolant Temperature (ECT) sensor
  • Engine Coolant Temperature (ECT) sensor harness is open or shorted
  • Engine Coolant Temperature (ECT) sensor electrical circuit poor connection
What does this mean?

Tech notes

SPECIAL NOTE: For some Toyota models, the P0125 codes is set by the front O2 sensor.

There are factory service bulletins for the following Toyota models:
2003 Toyota Corolla
2003 Toyota Matrix
The service bulletin recommends replacing the O2 sensors to fix the problem.

2004-2007 Toyota Prius
2007-2007 Toyota Prius Factory Service Bulletin OBDII Code P0125
What does this mean?