P1251

DIAGNOSTIC TROUBLE CODES P1251,1252
CHECK ENGINE lamp (MIL), control module output, no continuity or shorting to ground/batt+

Fault Symptom.
The CHECK ENGINE lamp (MIL) does not light up when the ignition switch is turned to the ON position.

Condition
In the event of a short circuit or open circuit a diagnostic trouble code will be generated.

Diagnostic Procedure.
1. Connect a Scan Tool.
Select 'ACTIVATE"
Select "CHECK Engine".

If the lamp cannot be activated, continue with step 2.
If the lamp lights up, continue with step 3.





2. Connect a BOB.
Ignition switch in the ON position.
Check that the CHECK ENGINE lamp (MIL) lights up when a jumper lead is connected across pins 14 and 22:

If the CHECK ENGINE lamp (MIL) does not light up:
- Check the bulb and its power supply.
- Check the lead and connectors between pin 22 of the control module and pin 12 of the Electronic Display Unit (EDU) for continuity, and possibly take remedial action.

If the lamp lights up, check the control module output.
- Take a voltage reading across pins 22 and 37. With the ignition switch in the ON position, a battery positive reading should be obtained.
- If it is not, continue at "Procedure Before ECM Replacement". Component Tests

3. Clear the diagnostic trouble code and drive the car to see whether the DTC is generated again.

If the diagnostic trouble code is generated again, continue at "Procedure Before ECM Replacement". Component Tests
If the trouble code is not generated again the remedial measure taken was correct, otherwise the fault is of intermittent type.