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 provide 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 | 1 | 2 | -- | --
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 | --

1. The engine cranks but does not run and opens the fuse that supplies voltage to the ignition coils.
2. 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.

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

### Conditions for Setting the DTC

The ECM detects an open, short to ground, or 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

• | Engine Control Module Connector End Views

• | Engine Controls 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

• | Scan Tool Data List

• | Scan Tool Data Definitions

• | Scan Tool Output Controls

### Circuit/System Verification

1. Engine idling, observe the DTC information with a scan tool. DTC P0351 and P0352 should not set.
2. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector of the ignition coil.

Important: The test lamp is used to load the circuit and may not illuminate.

2. Connect a test lamp between the ignition 1 voltage circuit of the ignition coil and ground.
3. Ignition ON, load test for battery voltage between the ignition 1 voltage circuit of the ignition coil and ground.

⇒ | If less than B+, repair the ignition 1 voltage circuit of the ignition coil for a short to ground or an open/high resistance.

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

4. Connect a DMM between the appropriate ignition control circuit and the negative terminal of the battery.
5. While cranking the engine, test for more than 3 Hz between the appropriate ignition control circuit and the negative terminal of the battery.

⇒ | If less than 3 Hz, test the ignition control circuit for a short to voltage, short to ground or an open/high resistance. If the circuit/connection test normal, replace the ECM.

6. If all circuits/connections test normal, replace the ignition coil.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Ignition Coil Replacement

• | Control Module References for engine control module replacement, setup, and programming