Check Fuel Injectors

Check Fuel Injectors







Recommended special tools and equipment
- V.A.G 1526A multimeter
- V.A.G 1527 B Voltage Tester
- V.A.G 1594A connector test kit
- V.A.G 1598/31 test box

Test requirements:
- Fuse for fuel injectors OK
- Fuel Pump (FP) Relay OK; checking. Fuel Pump (FP) Relay -J17- and Activation, Checking
- Parking brake engaged.
- Selector lever of automatic transmission in position "P" or "N".
- Ignition switched off.

NOTE: Voltage is supplied to the fuel injectors via the Fuel Pump (FP) relay.

Procedure







- Remove rear engine cover -arrows-.







- Remove front engine cover (arrows -1- and -2-).







- Disconnect connector strips -1- and -5- at fuel injectors.

NOTE: Disregard the other items.

Checking internal resistance







- Connect multimeter at valve for resistance measurement.
- Specified value: 12 to 13 Ohms (at room temperature)

NOTE: With an engine at operating temperature, the resistance of the fuel injectors increases by approx. 4 to 6 Ohms

If specified value is not obtained:
- Replace fuel injector

If specified value is obtained:

Checking voltage supply







- Connect e.g. V.A.G 1527 B voltage tester as follows:


Harness connector Measure to
Terminal
1 Engine Ground (GND)

- Operate starter briefly.
- LED must light up.
- Switch ignition off.

If LED does not light up:
- Check wire connection from harness connector terminal 1 to Fuel Pump (FP) Relay -J17- via fuse for open circuit according to wiring diagram.
- Specified value: Wire resistance max 1.5 Ohms
- If necessary, repair wire connection.

If LED lights up:

Checking activation

Test requirement:
- Internal resistance of valve OK

- Slide back rubber grommet of fuel injector connector, but leave connector connected.







- Connect voltage tester e.g. V.A.G 1527 B with measuring probes and connector adapters from V.A.G 1594 A between terminal 2 (signal) and terminal 1 (B+); the harness connector remains connected.
- Operate starter briefly.
- LED must blink.

NOTE: Voltage testers do not go out completely during low current pick-up between activations by the ECM, but rather continue to glow a little and then get slightly brighter during activation.

- Switch ignition off.

If LED does not blink:
- Connect test box to wiring harness of Engine Control Module (ECM), ECM is not connected. Test Box, Connecting For Wiring and Component Test







- Check the following wire connections for open circuit according to wiring diagram:







- Specified value: Wire resistance max 1.5 Ohms

- Check wires for short circuit to each other as well as to B+ and Ground (GND).
- Specified value: Infinite Ohms (no continuity)
- If necessary, repair wire connection.

If no malfunctions are detected:
- Replace Engine Control Module (ECM).

Assembly is performed in reverse order of removal, note the following:

Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check DTC memory see "Mode 3: Check DTC memory". Mode 3: Check DTC Memory
2. If necessary, erase DTC memory see "Mode 4: Reset/erase diagnostic data". Mode 4: Reset/Erase Diagnostic Data
3. Generate readiness code. Readiness Code, Generating

- End diagnosis and switch ignition off.