Fuel Injectors, Checking

Fuel Injectors, Checking

Observe all safety precautions: => [ Safety Precautions ] Generic Scan Tool

View clean working conditions: => [ Clean Working Conditions ] Clean Working Conditions

Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.

For wiring diagrams, component locations, and connector views, Refer to the applicable wiring diagram.

Special tools, testers and auxiliary items required

• Multimeter.

• Diode test lamp (12V).

• Wiring diagram.

Test requirements

• The Engine Speed (RPM) Sensor (G28) OK.

• Battery voltage at least 12.5 volts.

• All electrical consumers such as, lights and rear window defroster, switched off.

• Vehicles with automatic transmission, shift selector lever into position "P" or "N".

• A/C switched off.

• Ground (GND) connections between engine/transmission/chassis OK.

• Ignition switched off.

- Observe safety precautions.

- Observe rules for cleanliness.

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check

Start diagnosis

- Remove the engine covers. Refer to the appropriate service manual.






- Disconnect the 14 pin connector. the 14 pin connectors are located at the rear center of the engine, below the throttle motor assembly. There is one 14 pin connector for each bank. (Refer to the wiring diagram for circuit details)

- Using a Multimeter connected on the (stationary side of 14 pin connector) to the desired Fuel Injector terminals, measure the resistance of the injector.

Specified value: 1.7ohms (+/-.5ohms)

If the specified values were Not obtained:

- The supercharger assembly will have to be removed for access to the injectors and engine (jumper) harness.

- Check for an open or high resistance in the engine harness to the injector. If wiring resistance from 14 pin connector to injector is above 1.5 ohms, repair or replace the harness. If the wiring was within the resistance value, replace the injector. Refer to the Repair Manual for supercharger removal and injector replacement.

- Replace the malfunctioning Fuel injector(s).

- Go to Final procedures

If the specified values were obtained:

- Reconnect the 14 pin connectors. The 14 pin connectors are located at the rear center of the engine, below the throttle motor assembly. There is one 14 pin connector for each bank. (Refer to the wiring diagram for circuit details)

- Remove the Motronic Engine Control Module (ECM) (J623). Refer to appropriate service manual.

- Using a Multimeter, check the Fuel Injectors electrical harness connector terminals to the Motronic Engine Control Module (ECM) (J623) electrical harness connector T60 terminals for an open or short to ground circuit.






Specified values: 1.5 ohms max. for wire continuity, and for circuit to ground check; Infinite or "OL" is displayed

If the specified value was Not obtained:

- Check the wiring for an open, high resistance or short to ground.

- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

- If necessary, repair the faulty wiring connection.

- Go to Final procedures

If the specified value was obtained:

- Replace the Motronic Engine Control Module (ECM) (J623). Refer to appropriate service manual.

Final procedures

- Reinstall the engine cover with air filter, if necessary. Refer to the appropriate service manual.

- After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Programming and Relearning.