Fuel Injectors, Checking

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

Special tools and workshop equipment required 

• Multimeter.
• 12V diode test lamp
• Wiring diagram.

Test requirements 

• The Fuel Injectors -N30, N31, N32, N33- fuses OK.
• The Engine Speed (RPM) Sensor -G28- is 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 

Start diagnosis 

-- Remove the engine cover.

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

Checking internal resistance

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

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

If the specified value was Not obtained:

-- Replace the malfunctioning Fuel Injector --. Refer to the Repair service information.

If the specified value was obtained:

Checking activation and wiring

-- Connect a 12V diode test lamp 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 Engine Control Module (ECM) -J623-. Refer to the Repair service information.

-- Using a multimeter, check the Fuel Injector -- electrical harness connector terminals to the Engine Control Module (ECM) -J623- electrical harness connector T105 terminals for an open circuit.

Component	Fuel Injector -- electrical harness connector terminals:	Engine Control Module (ECM) -J623- electrical connector T105 terminals:
Cylinder 1 Fuel Injector -N30-	1	64
	2	85
Cylinder 2 Fuel Injector -N31-	1	23
	2	1
Cylinder 3 Fuel Injector -N32-	1	22
	2	2
Cylinder 4 Fuel Injector -N33-	1	65
	2	43

Specified value: 1.5 Ω Max.

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.

If no malfunction is detected in the wiring:

-- Replace the Engine Control Module (ECM) -J623-. Refer to the Repair service 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 .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .