Fuel Injectors, Checking

Fuel Injectors, Checking

The following procedure is used to diagnose (N30, N31, N32, N33, N83, N84)

Special tools, testers and auxiliary items required

• Multimeter.

• Diode test lamp (12V).

• Wiring diagram.

Test requirements

• The Fuel Injectors (N30, N31, N32, N33,N83,N84 ) 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.

Test procedure

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

Start diagnosis

- Remove the rear engine cover - arrows -.





Right bank

- Disconnect the 6 pin electrical harness connector - 1 - for Fuel Injectors (N30, N31, N32) from the right rear of the engine.





Left bank

- Disconnect the 14 pin electrical harness connector - 3 - for Fuel Injectors (N33, N83, N84) from the left rear of the engine.





Checking internal resistance

- Using a Multimeter, check the Fuel Injectors for resistance.

Right bank





Left bank





Specified value: 12 to 13 ohms (at room temperature).

• With an engine at operating temperature, the resistance of the fuel injectors increases by approx. 4 to 6 ohms.

If any of the specified values are not obtained:

- Replace the malfunctioning Fuel Injector.

If the specified values are obtained:

Checking activation

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

Right bank





Left bank





- Operate the starter briefly.

• Voltage testers do not go out completely during low current pick-up between activations by the ECM, but rather continue to glow a little and then get slightly brighter during activation.

The LED must light up.

- Switch the ignition off.

If the LED does not light up:

Checking wiring

If the manufacturers test box is being used. Perform the following step.

- Install the test box. Refer to Fuel Injection and Ignition Repair Information.

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

- Remove the Engine Control Module (ECM) (J623 ). Refer to => [ ECM, Removing and Installing ] ECM, Removing and Installing.

- 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.

Right bank





Left bank





Specified value: 1.5 ohms Max.

If any of the specified values are not obtained:

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

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

- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:

- Replace the Engine Control Module (ECM) (J623 ). Refer to => [ ECM, Removing and Installing ] ECM, Removing and Installing.

- Install the rear engine cover - arrows -.





Final procedures

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

1. Check the DTC memory. => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.

2. If necessary, erase the DTC memory. => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.

3. If the DTC memory was erased, generate readiness code. => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.

- End of diagnosis.