Operation CHARM: Car repair manuals for everyone.

Injectors, Checking



Injectors, checking

Electrical checks on injectors

- Remove connector from the injector which is to be tested.







- Connect hand-held multimeter to injector to measure resistance. Specified value: 13 ... 16

NOTE: When the engine is at operating temperature the resistance of the injectors is increased by approx. 4 ... 6 Ohm.

If specified value is not attained:

- Replace injector.

If specified value is attained:

- Check voltage supply.

Checking power supply
- Remove connector from injector to be tested.







- Connect diode test lamp for measuring voltage between Ground and socket 1 of connector.
- Operate starter for a few seconds (engine can be allowed to start).

Specified value: The diode test lamp should illuminate.
If the diode test lamp illuminates:
- Check wiring

If the diode test lamp does not illuminate:







- Check wiring from socket 1 via injector fuse to fuel pump relay for continuity and, if necessary, correct open circuit.

Checking wiring

- Switch ignition off.
- Remove connector from injector to be tested.
- Connect test box VAG 1598/31 to wiring harness for engine control module; do not connect engine control module. Connecting VAG 1598/31 Test Box







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







- Correct any open/short circuit as necessary.
- If wiring is OK replace engine control module and regenerate readiness code. Readiness Code, Generating