Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Test requirement
- No malfunction regarding fuel injector(s) stored
- Disconnect connectors from fuel injectors in sequence with engine running and observe engine operation.
or
- Compare spark plugs of all cylinders to each other. Check electrodes for carbon fouling.
If faulty cylinder is recognized:
- Connect multimeter to spark plug connector for resistance measurement.
Specified value: approx. 2 k Ξ©
If specified value is not obtained:
- Replace spark plug connector.
If specified value is obtained:
- Switch spark plug from faulty cylinder with one from another cylinder. Beforehand, perform a visual check of spark plug for possible damage e.g. cracks in ceramic shell of spark plug.
- If a malfunction now occurs at other cylinder, replace the spark plug.
If malfunction remains at original cylinder:
- Switch spark plug from faulty cylinder with one from another cylinder. Beforehand, perform a visual check of ignition coil for damage (ignition could be cracked or shattered).
- If a malfunction now occurs at other cylinder, replace the ignition coil.
If malfunction remains at original cylinder:
- Disconnect connector on ignition coil.
- Check Ground (GND) connection from terminal 4a to engine Ground (GND) for open circuit and short circuit to B+.
See appropriate System Wiring Diagrams article.
- Repair open circuit or short circuit if necessary.
If Ground (GND) connection is OK:
- Connect multimeter to terminal 15 of connector and Ground (GND) for voltage measurement.
- Remove fuel injector from cylinder to be tested.
- Operate starter.
Specified value on multimeter: approx. battery voltage
If specified value is not obtained:
- Check wire connections.
See appropriate System Wiring Diagrams article.
If specified value is obtained:
- Disconnect 3-pin connector from power output stages for ignition coils.
- Then connect voltage tester to 3-pin connector of both output stages.
- Connect voltage tester V.A.G 1527 to the following terminals of connector at power output stages. Then, operate starter for a few seconds.
| 3-pin connector at wiring harness, terminal | Specified value when operating starter |
|---|---|
| 1 & Ground (GND) 2 & Ground (GND) |
Voltage tester must light up |
| 3 & Ground (GND) |
If specified values are not obtained:
- Switch ignition off.
The following wire connections must be checked for short circuit to B+, Ground (GND) and for open circuit
| 3-pin, black connector to power output stage, terminal | 3-pin connector to ignition coil, terminal |
|---|---|
| 1 | 1 (cylinder 1) |
| 2 | 1 (cylinder 2) |
| 3 | 1 (cylinder 3) |
| 3-pin, brown connector to power output stage, terminal | 3-pin connector to ignition coil, terminal |
|---|---|
| 1 | 1 (cylinder 4) |
| 2 | 1 (cylinder 5) |
| 3 | 1 (cylinder 6) |
- Repair open circuit or short circuit if necessary.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.