P0125

DTC P0125 INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROL

1. OUTLINE OF DIAGNOSIS
Detect the malfunction of engine coolant temperature output property.
Judge as NG when the engine coolant temperature does not rise in driving conditions where it should.




2. COMPONENT DESCRIPTION




3. ENABLE CONDITIONS

4. GENERAL DRIVING CYCLE
Perform the diagnosis only once after engine start.

5. DIAGNOSTIC METHOD




Abnormality Judgment
Judge as NG when the malfunction criteria are met.




Timer for diagnosis after engine start
a. Timer stop at fuel cut.
b. During the driving conditions except a) above, timer count up by 64 milliseconds + TWCNT milliseconds at every 64 milliseconds.
TWCNT is defined as follows,
TWCNT = 0 at idle switch ON,
TWCNT show on the given table at idle switch OFF.




- Normality Judgment
Judge as OK and clear the NG when the malfunction criteria are met.

6. DTC CLEAR CONDITION
- When the OK idling cycle is completed 40 times in a row
- When "Clear Memory" is performed

7. MALFUNCTION INDICATOR LIGHT CLEAR CONDITIONS
- When the OK driving cycle is completed 3 times in a row
- When "Clear Memory" is performed

8. FAIL SAFE
- Engine coolant temperature sensor process: Engine coolant temperature is fixed at 70 degrees C (158 degrees F).
- ISC Feedback: Calculate target engine RPM as engine coolant temperature 70 degrees C (158 degrees F).
- ISC learning: Not allowed to learn.
- Air conditioner control: Not allowed to turn the air conditioner to ON.
- Radiator fan control: Send the duty signal 50% to the controller.

9. ECM OPERATION AT DTC SETTING
Memorize the freeze frame data. (For test mode $02)