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 and 4 Control Circuit
DTC P0352: Ignition Coil 2 and 3 Control Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition 1 Voltage | * | ** | -- | --
Ignition Coil 1 and 4 Control Circuit | P0300, P0351 | P0300, P0351 | P0300, P0351 | --
Ignition Coil 2 and 3 Control Circuit | P0300, P0352 | P0300, P0352 | P0300, P0352 | --
* The engine cranks but does not run and opens the fuse that supplies voltage to the ignition coils. ** The engine cranks but does not run.

### Circuit/System Description

Ignition 1 voltage is supplied to the ignition coil. The engine control module (ECM) provides a ground for the ignition coil (IC) control circuits. When the ECM removes the ground path of the ignition primary coil, the magnetic field produced by the coil collapses. The collapsing magnetic field produces a voltage in the secondary coil which ignites the spark plugs. The sequencing and timing are controlled by the ECM. The ignition coils consist of the following circuits:

• | The ignition 1 voltage

• | The IC 1 and 4 control

• | The IC 2 and 3 control

### Conditions for Running the DTC

• | The ignition is ON or the engine is running.

• | The DTCs run continuously once the above condition is met.

### Conditions for Setting the DTC

The ECM detects an open, short to ground, or a short to voltage on the IC circuit.

### Action Taken When the DTC Sets

DTC P0351 and P0352 are Type A DTCs.

### Conditions for Clearing the DTC

DTC P0351 and P0352 are Type A DTCs.

### 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

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Engine running, observe the DTC information with a scan tool. DTCs P0351 and P0352 should not set.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the ignition coil.
2. Ignition ON, command the fuel pump relay ON with a scan tool and verify that a test lamp illuminates between the ignition 1 voltage circuit terminal B and ground.

⇒ | If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition 1 voltage circuit fuse is open, test all components connected to the ignition 1 voltage circuit and replace as necessary.

Important: Set the DMM to the AC Hertz scale for this test.

3. Connect a DMM between the appropriate ignition control circuit and ground.

• | Ignition 1-4 control circuit terminal A

• | Ignition 2-3 control circuit terminal C

4. Engine cranking, verify the DMM displays greater than 3 Hz.

⇒ | If less than the specified range, test the ignition control circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the ignition coil.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Ignition Coil Replacement

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