Fuel Injectors, Bank 1, Checking

Fuel Injectors, Bank 1, Checking

The following test procedure is used to diagnose all fuel injectors controlled by the Engine Control Module (ECM) (J623).

Special tools, testers and auxiliary items required

• Multimeter.

• Diode test lamp (12V).

• Wiring diagram.

Test requirements

• The Engine Control Module (ECM) (J623) fuses OK.

• 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 Clean Working Conditions.

Test procedure

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

Start diagnosis

- Remove the intake manifold.

- Disconnect the Fuel Injector electrical harness connectors - 2,3,4,5 - from the Fuel Injector to be tested.





Checking internal resistance

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





Specified value: 12.0 to 20.0 ohms (at approx. 20° C)

If the specified value was not obtained:

- Replace the faulty Fuel Injector

If the specified value was obtained:

Checking activation

- Connect a diode test lamp (12V) to the Fuel Injector 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 flickers:

- Replace the faulty Fuel Injector

If LED does not flicker:

Checking activation and wiring

If the manufacturers test box is being used, perform the following step.

- Install the test box.

If the manufacturers test box is not being used, perform the following step.

- Remove the Motronic Engine Control Module (ECM) (J623). Refer to => [ Engine Control Module, Replacing ] Engine Control Module, Replacing.

- Using a Multimeter, check the electrical harness connector terminals of the Fuel Injector to be tested to the Motronic Engine Control Module (ECM) (J623) electrical harness connector T60 terminals for resistance.






Specified value: 1.5 ohms Max.

If the specification is not obtained:

- Check the wiring for an open circuit, a short circuit to each other, Battery (+), or Ground (GND).

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

- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:

- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Clearing Diagnostic Trouble Codes.

- Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to => [ Readiness Code ] Readiness Code.

- End diagnosis.

If the DTC returns and no malfunction is found in the wiring and voltage supply was OK:

- Replace the Motronic Engine Control Module (ECM) (J623). Refer to => [ Engine Control Module, Replacing ] Engine Control Module, Replacing.

Assembly is performed in the reverse order of the removal, note the following:

Final procedures

After 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 Mode 03 - Read DTC Memory.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Clearing Diagnostic Trouble Codes.

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