• Tiny
  • dom.r.matra
  • 2002 Toyota Corolla

Code po125 Insufficiant collant temperature for closed loop fuel control showing up on '02 Toyota. I changed the termostat and the temperature sensor; but, the check engine light keeps coming on, with the stated code showing up.
Could it be the 02 sensors?

Tuesday, June 11th, 2013 AT 12:15 PM

1 Answer

  • Tiny
  • KHLow2008
  • Expert
  • 41,976 posts

Circuit Description

Heated oxygen sensor monitors exhaust gas oxygen content and delivers an input signal to ECM. ECM uses input signal to determine fuel injection system operation. Heated oxygen sensor includes a heater. DTC is set when heated oxygen sensor No. 1 does not output a rich condition once engine is at normal operating temperature, engine speed is more than 1400 RPM and vehicle speed is 25-62 MPH for at least 2 minutes.

Possible causes are: Fuel system malfunction.
Defective fuel injector.
Ignition system malfunction.
Exhaust system leak.
Heated oxygen sensor No. 1 circuit is open or shorted.
Defective heated oxygen sensor No. 1.
Vehicle run out of fuel.
Defective ECM.

Only testings would tell you what is wrong.

Was this
Tuesday, June 11th, 2013 AT 12:24 PM

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