Injectors, Checking

Injectors, Checking







Special tools and equipment
- VAG 1526A
- VAG 1527B
- VAG 1594A
- VAG 1598/31

Procedure

Cylinder bank 2 (left):







- Remove front engine cover (arrows).







- Disconnect connectors to intake manifold change-over valve -N156- -1-

NOTE: Ignore item -2-.

Both cylinder banks, continued:







- Disconnect all connectors for injectors of relevant cylinder bank, release connectors underneath for this purpose (arrow).

Checking internal resistance







- Connect multimeter to injector to measure resistance.
- Specified value: 11 to 13 Ohms (at room temperature)
- When engine is at operating temperature resistance is increased by approx. 4 to 6 Ohms.

If specified value is not obtained:
- Replace injector.

If specified value is obtained:

Checking power supply

Test requirements:
- Fuse for injectors OK
- Fuel pump relay OK; Testing and Inspection

NOTE: The injectors receive their power supply via the fuel pump relay.

- Connect voltage tester VAG 1527B as follows:

Connector Measure to
terminal
1 Engine ground

- Switch ignition on.
- LED should illuminate.

If the LED does not illuminate:
- Check wiring connection between terminal 1 and fuse for injector for open circuit:
- Repair open circuit, if necessary.

If the LED illuminates:

Checking activation

Test requirements:

- Internal resistance of the valve OK







- Connect voltage tester VAG 1527 B with measuring probes and plug-in adapters from VAG 1594 A between terminal 2 (signal) and terminal 1 (positive); the connector remains plugged in.
- Operate starter briefly (engine may start).
- LED should flash.

NOTE: Voltage testers with a low current draw continue to glow faintly between activation from the engine control module (rather than extinguishing completely) and become slightly brighter when activated.

If LED does not flash:
- Connect test box VAG 1598/31 to wiring harness for engine control module; do not connect engine control module. Wiring and Component Testing Using VAG1598/31 Test Box







- Check for open circuit and short to positive or Ground in following wiring connections:







- Repair any open/short circuit as necessary.

If no wiring malfunction is detected:
- Replace engine control module.