Fuel Injectors, Checking

The following test procedure is used to diagnose Fuel Injectors -N30, N31, N32, N33, N83, and N84-.

Special tools and workshop equipment required

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

Test Requirements

Fuses for engine electronics OK.
Parking brake engaged.
Battery voltage at least 12.5 V.
Vehicles with automatic transmission, shift selector lever into position "P" or "N".
All electrical consumers such as, lights and rear window defroster, switched off (radiator fan must not run during test).
A/C switched off.
The fuel tank at least 1/4 full.
Ignition switched off.

Test Procedure

-- Perform a preliminary check to verify the customer's complaint. Refer to PRELIMINARY CHECK .

Right bank

Fig 1: Disconnecting 6 Pin Electrical Harness Connector For Fuel Injectors N30, N31, N32 From Right Rear Of Engine

Courtesy of AUDI OF AMERICA, LLC

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

Left bank

Fig 2: Disconnecting 14 Pin Electrical Harness Connector For Fuel Injectors N33, N83, N84 From Left Rear Of Engine

Courtesy of AUDI OF AMERICA, LLC

-- 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 injector electrical terminals for resistance.

Right bank

Fuel Injector	6- pin electrical harness connector terminals
N30	1 to 2
N31	3 to 4
N32	5 to 6

Left bank

Fuel Injector	14- pin electrical harness connector terminals
N33	5 to 6
N83	7 to 8
N84	9 to 10

Specified value: 12 to 13 Ω (at room temperature)

NOTE:

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

If the specified value is not obtained:

-- Replace the faulty fuel injector. Refer to Component Locations Overview .

If the specified value is obtained:

Checking activation

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

Right bank

Fuel Injector	6- pin electrical harness connector terminals
N30	1 to 2
N31	3 to 4
N32	5 to 6

Left bank

Fuel Injector	14- pin electrical harness connector terminals
N33	5 to 6
N83	7 to 8
N84	9 to 10

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

LED should flicker.

NOTE:

LEDs 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.

-- Switch the ignition off.

If LED flickers:

-- Replace the faulty Fuel Injector --. Refer to Component Locations Overview .

If LED does not flicker:

Checking voltage supply

-- Using a Multimeter --, check the Fuel Injector -- electrical harness connector terminal to ground (GND) for voltage.

Right bank

Fuel Injector	6 pin electrical harness connector terminal
N30	1
N31	3
N32	5

Left bank

Fuel Injector	14 pin electrical harness connector terminal
N33	5
N83	7
N84	9

-- Operate the starter briefly.

Specified value: Battery voltage.

-- Switch the ignition off.

If the specification is not obtained:

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

-- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring:

Checking wiring

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

-- Connect the Test Box 105 Pin VAG1598/42 with Adapter Cable1598/39-1. Refer to Component Locations Overview .

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

-- Remove the Engine Control Module (ECM) -J623-. Refer to ENGINE CONTROL MODULE, REPLACING

Right bank

Fuel injector	6 pin Electrical Harness Connector Terminal	Engine Control Module (ECM)J623 Electrical Harness Connector Terminal or Test box Socket
N30	1	33
N30	2	1
N31	3	46
N31	4	16
N32	5	32
N32	6	3

Left bank

Fuel injector	14 pin Electrical Harness Connector Terminal	Engine Control Module (ECM)J623 Electrical Harness Connector Terminal or Test box Socket
N33	5	31
N33	6	18
N83	7	47
N83	8	17
N84	9	48
N84	10	2

Using a Multimeter --, check the Fuel Injector -- electrical harness connector terminals to the Engine Control Module (ECM) -J623-

Specified value: 1.5 Ω max

If the specification is not obtained:

-- Check the wiring for a short circuit to Battery positive (+) or an open circuit.

-- If necessary, repair the wiring connection.

If no malfunctions are found in wiring:

-- Replace the Engine Control Module (ECM) -J623-. Refer to ENGINE CONTROL MODULE, REPLACING .

-- Assembly is performed in the reverse of the removal.

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

Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .