P1021

DIAGNOSTIC TROUBLE CODES P1021, P1022
Injector 2, output from control module low/high,
No continuity or shorting to ground/batt+.

Fault Symptom.
The engine runs on only three cylinders,
CHECK ENGINE lamp (MIL) on.

Condition
No continuity or shorting to ground/B+ in the circuit to pin 34.

Diagnostic Procedure.

NOTE: In connection with these diagnostic trouble codes there will probably also be a trouble code for incorrect fuel-air mixture.

1. Activate the ISAT command "INJECTOR 2" in the "ACTIVATE" menu and listen to check whether the valve is working.
A useful hint is to connect an LED into the circuit, as the valve may be difficult to hear.

If the valve is working, proceed to step 6.
If it is not, continue as described below.

2. Unplug the connector from the injector.
With the ignition switch in the DRIVE position, check whether battery voltage is present across pin 87 of the main relay and pin 1 of the injector connector.

If it is not, check the wiring between the valve and the relay.

3. Measure the resistance across pins 1 and 2 of the injector.
The correct resistance is 14-15 ohms.





4. Take a reading across pins 1 and 2 of the injector connector.
With the ignition in the DRIVE position (engine switched OFF), there should be current or pulses across these pins.
Then start the engine and check that a reading of about 0.5 V is obtained.

If a reading of about 0.5 V is obtained across pins 1 and 2, proceed to step 6.
If it is not, continue with the next step.

5. Check The Wiring between the MOTRONIC control module and the injector for continuity/shorting.

6. If possible, drive the car to see whether any fault symptoms are still present.

If they are, continue at "Before Control Module Replacement" for further diagnostic instructions. Before Replacing A Control Module