P1611

CHECK ENGINE REQUEST





Fault Symptoms.
CHECK ENGINE lamp (MIL) ON.

Conditions.
^ Ignition switch in ON position.
^ Short circuit to ground for more than 1.8 seconds.

Diagnostic Help.
The CHECK ENGINE request is made by the TCM when it wants the CHECK ENGINE lamp (MIL) to be turned on because an emission-related fault has occurred in the automatic transmission.

The status, "YES:/NO:", of the CHECK ENGINE request can be ascertained with the ISAT scan tool.
- Select "ON/OFF".
- Select "CHECK ENGINE REQUEST".

The CHECK ENGINE request can be activated via the TCM by means of the ISAT scan tool.
- Start the engine.
- Select "AUT TRANSMISSION".
- Select "ACTIVATE".
- Select "CHECK ENGINE".

If in proper working order, the CHECK ENGINE lamp (MIL) should light up for one second.

Check The Wiring.
Intermittent faults may occur as a result of temporary short circuits and breaks in the wiring. Jiggle the wiring at several points and in different directions to ascertain whether the wiring harness, including any connectors, is causing the trouble. Observe the multimeter, ISAT scan tool or test lamp while doing this.





Diagnostic Procedure.
1. Check The Wiring

Check the continuity of the lead between pin 39 of the Motronic control module and pin 5 of the transmission control module.

Is the lead OK?
YES: Continue with point 2.
NO: Rectify the fault and continue with point 3.





2. Check the TCM output stage

- Turn the ignition switch to the OFF position.
- Unplug the Motronic control module connector.
- Connect the test lamp to sockets 26 and 39 of the female connector.
- Connect the ISAT Scan Tool.
- Turn the ignition switch to the ON position.
- Select "AUT TRANSMISSION".
- Select "ACTIVATE".
- Select "CHECK ENGINE".
- At ON the test lamp should light up for one second.

Output stage OK (test lamp lit up for one second)?
YES: Continue with point 3.
NO: Continue fault diagnosis in the Automatic Transmission. Then carry out a final check according to point 3.





3. Final check

- Clear the diagnostic trouble code.
- Implementation of driving cycle:
^ Drive the car at varying engine loads and rpm for 5 minutes.
- Evaluation of driving cycle:
^ Check whether the diagnostic trouble code has recurred.

Has the diagnostic trouble code recurred?

YES: Continue at "Before Replacing a Control Module". Component Tests and General Diagnostics
NO: The steps taken to rectify the fault were correct.