Fuel Injector , Checking Audi TT 8N

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

Special tools, testers and auxiliary items required

1. Multimeter.
2. Diode test lamp (12V).
3. Wiring diagram.

Test requirements

1. Fuel Injector Fuse OK.
2. Motronic Engine Control Module (ECM) J220 Fuse OK.
3. Motronic Engine Control Module (ECM) Power Supply Relay J271 OK.
4. Battery voltage at least 12.5 volts.

1. All electrical consumers such as, lights and rear window defroster, switched off.
2. Vehicles with automatic transmission, shift selector lever into position "P" or "N".
3. A/C switched off.
4. Ground (GND) connections between engine/transmission/chassis OK.

1. Ignition switched off.

1. Observe safety precautions.
2. Observe rules for cleanliness.

Test procedure

1. Perform a preliminary check to verify the customers complaint. Refer to --> «General Diagnosis»(ref-276276-S40851803372008010300000) .

Start diagnosis

Scheme 40

1. Remove the Fuel Injector electrical harness retaining screws - arrows -.

Scheme 41

1. Remove the Fuel Injector electrical harness - arrows - from the fuel rail.
2. Disconnect the Fuel Injector electrical harness connectors - 1,2,3,4,5,6 - from the Fuel Injectors.

Checking internal resistance

Scheme 42

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

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

If the specified value was not obtained

1. Replace the faulty Fuel Injector. Refer to --> «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) .

If the specified value was obtained

Checking activation

Scheme 43

1. Connect a diode test lamp (12V) to the electrical harness connector terminals 1 and 2 of the Fuel Injector to be tested.
2. Operate the starter and test the activation of the Fuel Injector.

LED should flicker.

1. Switch the ignition off.

If LED flickers

1. Replace the faulty Fuel Injector. Refer to --> «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) .

If LED does not flicker

Checking voltage

1. Using a Multimeter , check the Fuel Injector electrical harness connector terminal 1 to ground (GND) for voltage.
2. Operate the starter.

Specified value: Battery voltage.

If the specification is not obtained

Scheme 44

1. Check the wiring from the Fuel Injector electrical harness connector terminal 1 to the Battery (+) 1 in the interior wiring harness for a short circuit to Ground (GND), or an open circuit.
2. Check the electrical harness connector for damage, corrosion, loose or broken terminals.
3. 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.

1. Install the test box VAG1598/31. Refer to --> «24 MULTIPORT FUEL INJECTION (MFI)»(ref-276275-S13244009452008010300000) .

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

1. Remove the Motronic Engine Control Module (ECM) J220. Refer to --> «Motronic Engine Control Module (ECM) J220, Replacing»(ref-276276-S39982482672008010300000) .

1. Using a Multimeter , check the Fuel Injector electrical harness connector terminals to the Motronic Engine Control Module (ECM) J220 electrical harness connector terminals for resistance.

Specified value: 1.5 ohms Max.

If the specification is not obtained

1. Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).
2. Check the electrical harness connector for damage, corrosion, loose or broken terminals.
3. If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring

1. Erase the DTC memory. Refer to --> «Diagnostic Mode 04: Reset/Delete Diagnostic Data»(ref-276276-S31279847122008010300000) .
2. Perform a road test to verify repair.

If the DTC does not return

Repair complete, Generate readiness code. Refer to --> Readiness Code .

1. End diagnosis.

If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK

1. Replace the Motronic Engine Control Module (ECM) J220. Refer to --> «Motronic Engine Control Module (ECM) J220, Replacing»(ref-276276-S39982482672008010300000) .
2. Assembly is performed in the reverse of the removal.

Final procedures

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

1. Check the DTC memory.
2. If necessary, erase the DTC memory. Refer to «Diagnostic Mode 04: Reset/Delete Diagnostic Data»(ref-276276-S31279847122008010300000) .
3. If the DTC memory was erased, generate readiness code. Refer to «Readiness Code»(ref-276276-S05799074302008010300000) .

End of diagnosis