Fuel Injectors, Checking

Observe all safety precautions: SAFETY PRECAUTIONS 

View 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 and workshop equipment required 

• Multimeter.
• Diode test lamp capable of at least 25 V.
• 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 

Start diagnosis 

-- Remove the engine cover with air filter. Refer to appropriate service information.

-- Disconnect the 8 pin connector from the fuel injector assembly harness (located just below and to the right of the electronic throttle motor assembly).

-- Using a Multimeter connected to ground, check terminals 2, 4, 6, 8 for the correct voltage.

Specified value: 22 - 25 V.

If the specified value was obtained:

Checking internal injector resistance

-- Using a Multimeter, check the Fuel Injector -- electrical terminals (1 to 2 for N30, 3-4 for N31, 5-6 for N32 or 7 to 8 for N33) for resistance.

Specified value: 1.4 - 2.6 Ω (at approx. 20° C)

-- If any of the specified values were out of range

-- Replace the malfunctioning Fuel injector(s). Refer to appropriate service information.

-- Go to Final procedures

If the specified value was not obtained:

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 appropriate service information.

-- Using a Multimeter, check the Fuel Injector -- electrical harness connector terminals 2, 4, 6, 8 to the Motronic Engine Control Module (ECM) - J623- electrical harness connector T60 terminals for an open or short to ground circuit.

Component	Fuel Injector -- electrical harness connector terminals	Motronic Engine Control Module (ECM) - J623- electrical connector T60 terminals or test box sockets
Cylinder 1 Fuel Injector - N30-	2	33
Cylinder 2 Fuel Injector - N31-	4	49
Cylinder 3 Fuel Injector - N32-	6	34
Cylinder 4 Fuel Injector - N33-	8	48

Specified values: 1.5 Ω 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:

Checking wiring 

-- Connect a Diode test lamp capable of at least 25 V from Battery voltage to the injector harness connector terminal (1 for N30, 3 for N31, 5 for N32 or 7 for N33) of the Fuel Injector -- to be tested.

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

Specified value: LED should flicker.

-- Switch the ignition off.

If the specified value was obtained:

-- 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 not obtained:

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 appropriate service information.

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

Component	Fuel Injector -- electrical harness connector terminals	Motronic Engine Control Module (ECM) -J623- electrical connector T60 terminals or test box sockets
Cylinder 1 Fuel Injector -N30-	1	31
	2	33
Cylinder 2 Fuel Injector -N31-	3	47
	4	49
Cylinder 3 Fuel Injector -N32-	5	32
	6	34
Cylinder 4 Fuel Injector -N33-	7	46
	8	48

Specified value: 1.5 Ω Max.

If the specified value was not obtained:

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

Final procedures 

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

-- 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 .