Fuel Injectors, Checking

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

Special tools and workshop equipment required 

• Multimeter.
• Diode test lamp (12V).
• Wiring diagram.

Test requirements 

• The Fuel Injectors -N30, N31, N32, N33- fuses OK.
  Fig 1: Fuses On E-Box In Engine Compartment, Left Side

  Courtesy of AUDI OF AMERICA, LLC
• The Engine Speed (RPM) Sensor -G28- OK, checking ENGINE SPEED SENSOR, CHECKING .
• 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 Repair information.

-- 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. Refer to Repair information.

If the specified value was obtained:

Checking activation and wiring 

-- Connect a diode test lamp (12V) 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:

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

-- Install the test box. Refer to Repair information.

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

-- Remove the Motronic Engine Control Module (ECM) -J220-. Refer to Repair information.

-- Using a Multimeter --, check the Fuel Injector -- electrical harness connector terminals to the Motronic Engine Control Module (ECM) -J220- electrical harness connector T60 terminals for an open circuit.

Component	Fuel Injector -- electrical harness connector terminals	Motronic Engine Control Module (ECM) -J220- electrical connector T60 terminals or test box sockets
Cylinder 1 Fuel Injector -N30-	1	33
	2	2
Cylinder 2 Fuel Injector -N31-	1	47
	2	1
Cylinder 3 Fuel Injector -N32-	1	32
	2	17
Cylinder 4 Fuel Injector -N33-	1	48
	2	16

Specified value: 1.5 Ω Max.

If the specification is 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 Motronic Engine Control Module (ECM) -J220-. Refer to Repair information.

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