CHECK ENGINE - requirements

Symptom: The CHECK ENGINE warning lamp does not go on despite the presence of a fault causing the limp-home program to activate.

CHECK ENGINE - requirements

Fault symptoms

The CHECK ENGINE warning lamp does not go on despite the presence of a fault causing the limp-home program to activate.

Conditions

A fault occurring during a driving cycle will generate a diagnostic trouble code and the CHECK ENGINE warning lamp will go on.

Diagnostic help

The CHECK ENGINE warning lamp can be activated from the transmission control module with the diagnostic tool.

Select " Data Display / Output Control (New)".

Select " CHECK ENGINE Lamp".

Diagnostic procedure

1 Check the transmission control module output

-	Connect BOB to the engine management system connector but do not connect the control module.

-	Connect a test lamp between: pins 61 and 60 (Trionic)

-	Turn the ignition key to the ON position. The test lamp should go on for about 1 second and then go out. If there is an OBD II trouble code stored, the test lamp will flash. Otherwise, the lamp will remain off.

Is the lamp functioning correctly?

Yes

Continue fault diagnosis in Service Manual 2:7 "Engine management system". Then continue with step 3.

no

Rectify the relevant lead and continue with step 2.

2 Final check

-	Clear all diagnostic trouble codes in the system.

•

Perform a check of functionality.

All OK?

Yes

The steps taken to rectify the fault were correct.

no

Continue with Diagnostic procedure before replacing control module .