Ignition Coil: Testing and Inspection
Ignition Coils with Power Output Stage, Checking
Special tools, testers and auxiliary items required
• Multimeter.
• Wiring diagram.
Test requirement
• The Ignition Coils with Power Output Stage (N70, N127, N291, N292, N323, N324) fuses are OK.
• The Engine Control Module (ECM) Power Supply Relay (J271) is OK.
• The Engine Speed (RPM) Sensor (G28) is OK.
• The Camshaft Position (CMP) Sensor (G40) is 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 connections between engine/transmission/chassis OK.
• Ignition switched Off.
Test procedure
- Observe safety precautions. Refer to => [ Safety Precautions ] Generic Scan Tool
- Observe Clean Working Conditions. Refer to => [ Clean Working Conditions ] Clean Working Conditions
- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check.
Start diagnosis
- Remove the Ignition Coils with Power Output Stage (N70, N127, N291, N292, N323, N324) electrical harness screws.
- Disconnect the Ignition Coils with Power Output Stage (N70, N127, N291, N292, N323, N324) electrical harness connectors from the Ignition Coils with Power Output Stage (N70, N127, N291, N292, N323, N324).
Checking voltage and ground
- Switch the ignition On.
- Using a multimeter, check the Ignition Coil electrical harness connector terminal 3 to ground for voltage.
Specified value: Battery voltage.
- Switch the ignition Off.
- Using a multimeter, check the Ignition Coil electrical harness connector terminals 1 to ground, then 2 to ground for resistance.
Specified value: 1.5 ohms Max.
If any of the specified values were Not obtained:
- Check the wiring connection for an open circuit, high resistance or short circuit to voltage or ground.
- Check the wiring connection for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
If both of the specified values were obtained:
Checking activation
Do not touch the Ignition Coils connecting parts or adapter cables during the following test.
- Disable the power supply to the Fuel Injectors (N70, N127, N291, N292, N323, N324) by removing the fuse.
- Using a diode test lamp, check the Ignition Coil electrical harness connector terminals 3 to 4 for voltage.
- Crank the engine.
The LED should flicker.
- Switch the ignition Off.
If the LED flickers and the voltage/ground checks were OK:
- Replace the faulty Ignition Coils with Power Output Stage (N70, N127, N291, N292, N323, N324).
If the LED does Not flicker:
Checking wiring
- Remove the Engine Control Module (ECM) (J623). Refer the Repair Information.
- Using a multimeter, Check the Ignition Coil electrical harness connector to the Engine Control Module (ECM) (J623) electrical harness connector T60 for an open circuit.
Specified value: 1.5 ohms Max.
If the specified value was Not obtained:
- Check the wiring connection for an open circuit, high resistance or short circuit to voltage or ground.
- Check the wiring connection for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
If no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Engine Control Module (ECM) (J623). Refer to the Repair Information.
- Assembly is performed in the reverse of the removal.
Final procedures
After repair work, the following work steps must be performed in the mentioned sequence:
1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.