Ignition Coil, Checking
Ignition Coil N152*, checking
(*Editor's Note: Incorrectly identified in literature as N152, correct identification is N, N128, N158.)
Special tools, testers and auxiliary items required
- Multimeter
- Diode test lamp
- Wiring diagram
Test requirements
- Fuse S232 OK.
- The Fuel Pump (FP) Relay J17 OK.
- 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.
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to Preliminary check.
Start diagnosis
Note: Mark the spark plug wires before removing to aid in reinstalling.
- Remove the spark plug wires.
Checking spark plug wire resistance
- Using a Multimeter, check each spark plug wire from end to end for resistance.
Specified value: 4 to 6 kOhms
If the specified value was not obtained:
- Replace the faulty spark plug wire.
If the specified value was obtained:
Checking ignition coil resistance
- Using a Multimeter, check the ignition coil from end to end for resistance.
Specified value: 8 to 14 kOhms.
If the specified value was not obtained:
- Replace the faulty Ignition Coil N152.
If the specified value was obtained:
Checking voltage supply
- Remove Fuse S234 to disable the fuel injectors.
- Disconnect the Ignition Coil N152 electrical harness connector - 2 - .
- Crank the engine.
- Using a Multimeter, check the Ignition Coil N152 electrical harness connector terminal 1 to Ground (GND) for voltage.
Specified value: battery voltage.
- Switch the ignition off.
If the specified value was not obtained:
- Check the Ignition Coil N152 electrical harness connector terminal 1 to the Fuel Pump (FP) Relay J17 socket 19/15 for an open circuit or a short circuit to Ground (GND).
- Check the electrical connectors for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
If the specified value was obtained:
Checking Ground (GND)
- Using a Multimeter, check the Ignition Coil N152 electrical harness connector terminal 2 to Ground (GND) for resistance.
Specified value: 1.5 Ohms Max.
If the specified value was not obtained:
- Check the Ignition Coil N152 electrical harness connector terminal 2 to Ground (GND) for an open circuit or a short circuit to Battery (+).
- Check the electrical connectors for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
If the specified value was obtained:
Checking activation
CAUTION! Do not touch the Ignition Coils connecting parts or adapter cables during the following test.
- Crank the engine.
- Using a diode test lamp, check the following electrical connections.
The LED should flicker for each terminal.
- Switch the ignition off.
If the LED flickers for each terminal and the voltage was OK:
- Replace the faulty Ignition Coil N152.
If the LED does not flicker:
Checking wiring
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 Engine Control Module (ECM) J220.
- Using a Multimeter, Check the Ignition Coil N152 electrical harness connector to the Engine Control Module (ECM) J220 electrical harness connector for resistance.
Specified value: 1.5 Ohms Max.
If the specified value was not obtained:
- Check the wiring connections for an open circuit, short circuit to Battery (+) or Ground (GND).
- Check the electrical connectors for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
If the specified values were obtained and voltage supply was OK:
- Replace the faulty Ignition Coil N152.
- Erase the DTC memory. Diagnostic Mode 04: Reset/Delete Diagnostic Data
- Perform a road test to verify repair.
If the DTC does not return:
Repair complete, Generate readiness code. Audi Drive Cycle/Readiness Code
- End diagnosis.
If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Engine Control Module (ECM) J220.
- 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.
3. If the DTC memory was erased, generate readiness code.
End of diagnosis.