Diagnostic Instructions
Circuit/System Description
The ignition system on this engine uses individual ignition coils and ignition control (IC) circuits for each cylinder. Ignition voltage is supplied to each bank of ignition coils. The engine control module (ECM) controls the ignition system operation.
The ECM controls each coil using the IC circuits. The ECM commands the IC circuit low when a spark event is requested. The sequencing and timing are controlled by the ECM.
Diagnostic Aids
| • | The ignition coils for each bank are fused separately. If a fuse opens or the ignition voltage circuit opens between the fuse and the splice, all the ignition coils for one bank of the engine would be inoperative. If the ground circuit opens at the
engine block, the ignition coils would be inoperative for one bank of the engine. |
| • | Inspect the ignition coils for aftermarket devices. An aftermarket device connected to the ignition coil circuits, may cause a condition with the ignition coils. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Electronic Ignition (EI) System Description
Electrical Information Reference
Scan Tool Reference
Control Module References
for scan tool information
Special Tools
Circuit/System Testing
Important: Do not perform this diagnostic procedure if you were not sent here from a misfire DTC or the Engine Cranks but Does Not Run diagnostic.
- Ignition OFF, disconnect the harness connector of the ignition coil.
- Ignition ON, load test for battery voltage between the ignition voltage circuit terminal 2 and ground.
| ⇒ | If less than B+, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition voltage circuit and replace
as necessary. |
- Ignition OFF, test for less than 5 ohms of resistance between the ground circuit terminal 3 and ground.
| ⇒ | If greater than the specified range, test for an open/high resistance in the ground circuit. If the circuit/connection tests normal, replace the ECM. |
- Test for less than 5 ohms of resistance between the ground circuit terminal 4 and ground.
| ⇒ | If greater than the specified range, repair the open, or high resistance in the ground circuit. |
- If all circuits/connections test normal, replace the ignition coil.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
