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 OK.
• The Engine Control Module (ECM) Power Supply Relay (J271) OK.
• The Engine Speed (RPM) Sensor (G28) OK.
• The Camshaft Position (CMP) Sensor (G40)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 ] Safety Precautions
- 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 coil packs.
Checking voltage supply
- Switch the ignition ON.
- Using a multimeter, check the Ignition Coil electrical harness connector terminals 1 to 3 for voltage.
Specified value: Battery voltage.
- Switch the ignition OFF.
If the specified value was Not obtained:
- Check the Ignition Coil electrical harness connector terminal 3 to fuse S-7 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 the specified value was obtained:
Checking activation
Do not touch the Ignition Coils, connecting parts or adapter cables during the following test.
- Using a diode test lamp, check the Ignition Coil electrical harness connector terminals 3 to 4 for voltage.
- Operate the starter.
The LED should cycle on and off.
- Switch the ignition OFF.
If the LED cycles on and off and the voltage was OK:
- Replace the faulty Ignition Coils with Power Output Stage (N70, N127, N291, N292, N323, N324).
If the LED does Not cycle on and off:
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 no malfunction is detected in the wiring, voltage was present and the LED did Not cycle on and off:
- 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.