For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptors

DTC P0351: Ignition Coil 1 Control Circuit
DTC P0352: Ignition Coil 2 Control Circuit
DTC P0353: Ignition Coil 3 Control Circuit
DTC P0354: Ignition Coil 4 Control Circuit
DTC P0355: Ignition Coil 5 Control Circuit
DTC P0356: Ignition Coil 6 Control Circuit
DTC P0357: Ignition Coil 7 Control Circuit
DTC P0358: Ignition Coil 8 Control Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition Coil 1 Control Circuit | P0351 | P0351 | P0351 | --
Ignition Coil 2 Control Circuit | P0352 | P0352 | P0352 | --
Ignition Coil 3 Control Circuit | P0353 | P0353 | P0353 | --
Ignition Coil 4 Control Circuit | P0354 | P0354 | P0354 | --
Ignition Coil 5 Control Circuit | P0355 | P0355 | P0355 | --
Ignition Coil 6 Control Circuit | P0356 | P0356 | P0356 | --
Ignition Coil 7 Control Circuit | P0357 | P0357 | P0357 | --
Ignition Coil 8 Control Circuit | P0358 | P0358 | P0358 | --

### Circuit/System Description

The ignition system on this engine uses an individual module/coil for each cylinder. The engine control module (ECM) controls the spark event for each cylinder through the 8 individual ignition control (IC) circuits. When the ECM commands the IC circuit ON, electrical current will flow through the primary winding of the ignition coil, creating a magnetic field. When a spark event is requested, the ECM will command the IC circuit OFF, interrupting current flow through the primary winding. The magnetic field created by the primary winding will collapse across the secondary coil windings, producing a high voltage across the spark plug electrodes. The ECM uses information from the crankshaft position (CKP) sensor, and the camshaft position (CMP) sensor for sequencing and timing of the spark events. The ECM monitors each IC circuit for improper voltage levels. Each ignition module/coil assembly has the following electrical circuits attached:

• | IGN 1 Voltage Circuit

• | The ground circuit

• | An IC circuit

• | Low reference circuit

### Conditions for Running the DTC

• | The engine is cranking or running.

• | Ignition voltage is more than 6 volts.

• | DTC P0351-P0358 runs continuously once the above conditions are met.

### Conditions for Setting the DTC

• | The ECM detects that the commanded state of the ignition control circuit and the actual state do not match.

• | It occurs at least 50 times during the 63 tests.

### Action Taken When the DTC Sets

DTC P0351-P0358 are type B DTCs.

### Conditions for Clearing the DTC

DTC P0351-P0358 are type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

• | Scan Tool Data List

• | Scan Tool Data Definitions

• | Scan Tool Output Controls

### Circuit/System Verification

1. Start and run the engine.
2. With a scan tool, monitor for all eight ignition control (IC) ignition status parameters display OK.

⇒ | If the IC circuit status parameter displays Short to Ground/Open, or Short to B+, continue with the Circuit/System Testing.

3. Observe the Misfire Current counters using the scan tool. The counters should not increase.

⇒ | If the counters increase for any of the cylinders, continue with Circuit/System Testing.

4. If the vehicle passes the Circuit/System Verification Test, operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle under the conditions observed from the Freeze Frame/Failure Records.

### Circuit/System Testing

1. Turn the ignition OFF.
2. Disconnect the ECM.

Note: A high resistance on any IC circuit can cause a misfire before the DTC sets.

3. Test the affected IC circuit for the following.

• | Short to voltage

• | Short to ground

• | Open/High Resistance

⇒ | If a condition is found, repair the circuit as needed.

4. Connect the ECM.
5. Exchange the affected ignition coil/module with the ignition/coil module of a good cylinder.
6. Start the engine, and observe the scan tool.

⇒ | If the DTC or misfire on the suspected ignition/coil module occurs, replace the ignition coil.

⇒ | If the DTC occurs or misfire on the suspected ignition/coil module does not occur, replace the ECM.

### Repair Instructions

• | Ignition Coil Replacement - Bank 1, Ignition Coil Replacement - Bank 2

• | Refer to Control Module References for ECM replacement, setup, and programming.

### Repair Verification

Note: An ignition system misfire condition may cause the 3-way catalytic converter to overheat under certain driving conditions.

If the customer concern was a flashing MIL, perform the following procedure:

1. Install components that were removed or replaced during diagnosis.
2. Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced.
3. Clear the DTC.
4. Turn the ignition OFF for 60 seconds.
5. If the repair was related to a DTC, duplicate the Conditions for Running the DTC and use the Freeze Frame/Failure Records, if applicable, to verify that the DTC does not reset. If the DTC resets or another DTC is present, refer to Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostic procedures.
6. To verify that the performance of the catalytic converter has not been affected by the condition that set this DTC, perform the Repair Verification for DTC P0420 or P0430. Refer to DTC P0420 or P0430.