Ignition Coil: Testing and Inspection
Ignition Coil With Power Output Stage N70, N127, N291, N292 , Checking
The following procedure is used to diagnose all ignition coils with power output stages.
Special tools, testers and auxiliary items required
- Multimeter V.A.G 1526 or equivalent.
- Test Box 105 Pin VAG1598/42.
- Adapter Lead Vag1598/39 VAG1598/39.
- Adapter cable V.A.G 1598/39-1.
- Voltage Tester VAG1527B or equivalent.
NOTE: The ignition coils and power output stages are one component and cannot be replaced individually.
Test requirement
The fuses for the engine electronics OK.
Procedure
Check for a misfiring cylinder as follows:
- Compare the spark plugs of all the cylinders to each other. Check the electrodes for carbon fouling.
If a faulty cylinder is recognized:
- Switch the spark plug from the faulty cylinder with one from another cylinder.
If the malfunction follows the spark plug:
- Replace the spark plug.
If the malfunction remains at the original cylinder:
- Switch the ignition coil from the faulty cylinder with one from another cylinder.
If the malfunction follows the ignition coil:
- Replace the ignition coil.
Electrical harness removal
- Remove engine cover - arrows - .
- Remove the screws - 1 - retaining the electrical harness to the valve cover.
- Disconnect the electrical harness connectors - arrows - from the ignition coils:
Checking voltage supply
- Using the Voltage Tester VAG1527B or equivalent, check the following wiring connections for voltage.
Harness connector Terminal Measure to
2 Battery positive (+)
4 Battery positive (+)
The LED must light up.
If the LED does not light up:
Checking resistance
- Using the Multimeter V.A.G 1526 A or equivalent, check the following wiring connection for an open circuit.
Harness connector Terminal Measure to
1 Engine Ground (GND)
- Specified resistance 1.5 Ohms max.
- If necessary, repair the wiring connection.
If the LED lights up:
- Switch the ignition on.
- Using the Multimeter V.A.G 1526 A or equivalent, check the following wiring connection for voltage.
Harness connector Terminal Measure to
1 Engine Ground (GND)
Specified value: approx. battery voltage
- Switch the ignition off.
If the specified value is obtained:
Checking activation of power output stages
- Remove the rubber seal in the direction of the - arrow -.
- Remove the plenum chamber cover - 1 - .
- Using a screwdriver, remove wiper arm caps - 3 - from wiper arms.
- Loosen wiper arm nuts - 4 - several turns.
- Loosen wiper arms - 2 - from wiper axle by tilting slightly.
- Remove wiper arm nuts completely and remove wiper arms.
- Remove securing clips - 1 - and cowl - 5 - .
- Remove the screws - arrows - and cover from the E-Box in the plenum chamber.
- Using a screwdriver, remove the retainer bar - arrow - and Engine Control Module (ECM) J623 and position aside.
- Remove the Motronic Engine Control Module (ECM) Power Supply Relay J271 - 2 - from the E-Box.
- Using the Multimeter V.A.G 1526 A or equivalent, check the wiring connection from the Motronic Engine Control Module (ECM) Power Supply Relay J271 carrier position 2, terminal 2 to the ignition coil wiring harness electrical connector terminal 1 for an open circuit.
Specified resistance 1.5 Ohms max.
If the specified value is not obtained:
- Repair the wiring connection.
If no malfunctions are found in the wiring:
- Connect the test box 1598/42 to the wiring harness of the Engine Control Module (ECM) J623.
- Using the Test Box 105 Pin VAG1598/42 and Multimeter V.A.G 1526 A or equivalent, check the following wiring connection for an open circuit.
Harness connector Terminal 3 Test box Socket
N70 Cyl. 1 58
N127 Cyl. 2 41
N291 Cyl. 3 43
N292 Cyl. 4 56
Specified resistance 1.5 Ohms max.
If the specification is not obtained:
- Repair the wiring connection.
If no malfunctions are found in the wiring:
- Replace the faulty ignition coil.
Assembly is performed in the reverse order of removal, note the following:
Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check the DTC memory.
2. If necessary, erase the DTC memory.
3. If the DTC memory was erased, generate readiness code.
- End diagnosis and switch ignition off.