Manufacturer's Scan Tool

Fuel Injectors, Checking

Special tools, testers and auxiliary items required

• (VAG1526A)

• (VAG1527B)

• (VAG1594A)

• (VAG1598/31)

Procedure

Cylinder bank 2 (left)

- Remove front engine cover (arrows).





- Disconnect connectors to Intake manifold change-over valve (N156) - 1 -.





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 the engine is at operating temperature the resistance is increased by approx. 4 to 6 ohms.

If specified value is not obtained:

- Replace injector. Refer to => [ Fuel Injectors ] Removal and Replacement

If specified value is obtained:

Checking power supply

Test requirements

• Fuse for injectors OK.

• Fuel pump relay OK; checking. Refer to => [ Fuel Pump Relay and Activation, Checking ] Fuel Pump Relay and Activation, Checking.

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

- Connect voltage tester (VAG1527B) as follows:









- 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 actuation

Test requirements

• Internal resistance of the valve OK

- Connect voltage tester (VAG1527B) with measuring probes and plug-in adapters from (VAG1594A) between terminal 2 (signal) and terminal 1 (positive); connector remains plugged in.





- Operate starter briefly (engine may start).

• LED should flash.

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

If LED does not flash:

- Connect test box (VAG1598/31) to wiring harness for engine control module; do not connect engine control module. Refer to => [ Wiring and Component Check with Test Box VAG 1598/31 ] Wiring and Component Check With Test Box VAG 1598/31.

- 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:

• With anti-theft housing. Refer to => [ Engine Control Module with Metal Anti-Theft Housing ] Engine Control Module With Metal Anti-Theft Housing.

• Without anti-theft housing. Refer to => [ Engine Control Module without Metal Anti-Theft Housing ] Engine Control Module Without Metal Anti-Theft Housing.