With Generic Scan Tool

Fuel Injectors, Checking

Recommended special tools and equipment
- VAG 1526 multimeter or VAG 1715 multimeter
- VAG 1527 voltage test lamp
- VAG 1594 connector test kit
- Wiring diagram

Test requirements







- The respective fuses of fuel injectors (N30 to N33) must be OK.
- Fuel Pump (FP) Relay -J17- must be OK, check.
- Battery voltage must be at least 11.5 volts.
- All electrical consumers such as, for example, lights and rear window defroster must be switched off.
- Parking brake must be engaged or else daylight driving lights will be switched on.
- For vehicles with automatic transmission, selector lever must be in position -P- or -N-.
- If vehicle is equipped with an A/C system, it must be switched off.
- Ground (GND) connections between engine and chassis must be OK.
- Engine speed (RPM) sensor must be OK. Testing and Inspection
- Ignition switched off.

Test sequence
- Remove upper part of intake manifold.
- Intake manifold, upper part, disassembling and assembling:
- Vehicles with engine code AEG, AVH, AZG.
- Vehicles with engine code BDC.


NOTE: Seal the intake channels in lower part of intake manifold using a clean rag.


- Disconnect fuel injector connectors.

Resistance values of fuel injectors, checking







- Test resistance of fuel injectors between terminals. Specified value: 14...18 Ohms


NOTE: Resistance value is valid at approx.. 20 degrees C. At higher temperatures, resistance value increases.


If specified value is not obtained:
- Replace faulty fuel injector:
- Vehicles with engine code AEG, AVH, AZG, item 7.
- Vehicles with engine code BDC, item 9.

Note the following when installing the fuel injectors:
- Replace O-rings on all fuel injectors and wet them slightly with clean motor oil.
- Insert fuel injectors into fuel distributor perpendicular and in the right position, and secure them with retaining clips.
- Position fuel distributor with secured fuel injectors on lower part of intake manifold and apply uniform pressure to press it in.
- The connectors must audibly engage on valves when attached.

- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

Checking voltage supply

Vehicles with engine code AEG







- Connect diode test lamp to connector of fuel injector to be tested terminal 1 and Ground (GND).

Vehicles with engine code AVH, AZG, BDC







- Connect diode test lamp to connector of fuel injector to be tested terminal 1 and Ground (GND).

Continuation for all vehicles

- Operate starter and test voltage supply for fuel injector. LED must light up.
- Switch ignition off.

If LED does not light up:
- Check wire between 2-pin connector terminal 1 and the Fuel Pump (FP) Relay -J17- for open circuit according to wiring diagram. Wire resistance: max. 1.5 Ohms

Activation and voltage supply, checking

Vehicles with engine code AEG







- Connect diode test lamp to the connector terminals of the fuel injector to be checked.

Vehicles with engine code AVH, AZG, BDC







- Connect diode test lamp to the connector terminals of the fuel injector to be checked.

Continuation for all vehicles

- Operate starter and test activation of fuel injector. LED should flicker.
- Switch ignition off.

If LED does not flicker:
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test

Vehicles with engine code AEG







- Check wires between test box and 2-pin connector for open circuit according to wiring diagram. Wire resistance: max. 1.5 Ohms







- Also check wires for short circuit to B+ and Ground (GND). Specified value: Infinite Ohms

Vehicles with engine code AVH, AZG, BDC







- Check wires between test box and 2-pin connector for open circuit according to wiring diagram. Wire resistance: max. 1.5 Ohms







- Also check wires for short circuit to B+ and Ground (GND). Specified value: Infinite Ohms

Continuation for all vehicles

If there is no malfunction in wire connection:
- Replace Motronic Engine Control Module (ECM) -J220-.