Generic Scan Tool

Fuel Injectors, Checking

The following test procedure is used to diagnose all fuel injectors.

Special tools, testers and auxiliary items required

• Multimeter.

• Diode test lamp (12 V).

• Wiring diagram.

Test requirements

• The Fuel Pump relay is operational.

• 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 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 cover with air filter. Refer to the Repair Information.

- Disconnect the Fuel Injector electrical harness connectors from Fuel Injectors (N30, N31, N32, N33, N83).

Checking internal resistance

- Using a multimeter, check the Fuel Injector electrical terminals 1 to 2 for resistance.

Specified value: 10.0 to 18.5 ohms (at approx. 20 °C)

If the specified value was Not obtained:

- Replace the Fuel Injector Refer to the Repair Information.

If the specified value was obtained:

Checking activation and wiring

- Connect a Diode test lamp (12 V) to the electrical harness connector terminals 1 and 2 of the Fuel Injector to be tested.

- Operate the starter and test the activation of the Fuel Injector.

LED should flicker.

- Switch the ignition OFF.

If LED does not flicker:

- Remove the Fuel Pump Relay (J17).

- Connect a jumper between the Fuel pump relay terminals 30 and 87

- Turn the ignition switch ON.

- Using a test lamp connected to ground, check terminal 1 of the Fuel Injector to be tested. The lamp should be ON.

- If the test lamp did not turn on, locate the open or high resistance in the voltage supply circuit.

If the voltage supply was OK:

- Remove the Engine Control Module (ECM) (J623). Refer to the Repair Information.

- Using a multimeter, check the Fuel Injector electrical harness connector terminals to the Engine Control Module (ECM) (J623) electrical harness connector T60 terminals for an open circuit. Refer to Wiring Diagrams for pin locations.






Specified value: 1.5 ohms Max.

If the specified value was Not obtained:

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

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

- If necessary, repair the faulty wiring.

If no malfunction is detected in the wiring and the voltage supply was OK:

- Replace the Engine Control Module (ECM) (J623). Refer to the Repair Information.

- Install the engine cover with air filter. Refer to the Repair Information.

Final procedures

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 ] Monitors, Trips, Drive Cycles and Readiness Codes.