P1691

CHECK ENGINE





Fault Symptoms.
CHECK ENGINE lamp (MIL) on continuously or out of order.

Conditions.
P1691
^ Engine speed higher than 80 rpm.
^ Battery voltage 7.5-17 V.
^ Open circuit.

P1692
^ Engine speed higher than 80 rpm.
^ Battery voltage 7.5-17 V.
^ Shorting to ground.

P1693
^ Engine speed higher than 80 rpm.
^ Battery voltage 7.5-17 V.
^ Short circuit to battery positive (B+).

Diagnostic Help.
The CHECK ENGINE lamp (MIL) can be activated with the ISAT scan tool.
- Select "ACTIVATE".
- Select "CHECK ENGINE LAMP".

The command activates the lamp at a frequency of 0.5 Hz for 30 seconds.

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 multi meter, ISAT scan tool or test lamp while doing this.





Diagnostic Procedure.
1. Check the bulb
- Check that the bulb is good.

Is the bulb OK?
YES: Continue with point 2.
NO: Change the bulb. Then continue with point 3.

2. Check the control module output
- Unplug the main instrument display panel connector.
- Connect a test lamp to battery positive (B+) and pin 22.
- Connect the ISAT Scan Tool.
- Turn the ignition switch to the ON position.
- Select "ACTIVATE".
- Select "CHECK ENGINE LAMP".

The lamp should flash at a frequency of 0.5 Hz for 30 seconds.

Lamp flashing?
YES: Continue fault diagnosis in the electrical system, main instrument display panel.
NO: Check and if necessary repair or replace the lead between pin 22 of the main instrument display panel's connector and pin 8 of the Motronic control module's connector.
Then continue with 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.