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 Descriptor

DTC B1428: Starter Relay Malfunction

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Starter Relay Coil Supply | B1428 | B1428 | B1428 | --

### Circuit/System Description

When the ignition switch is placed in the START position, a discrete signal is supplied to the steering column control module (SCCM) notifying it that the ignition is in the START position. The SCCM then sends a serial data message to engine control module (ECM) and the underhood electrical center (UEC), that CRANK has been requested. The UEC then supplies 12 volts to the coil side of the STARTER relay, when the ignition is in the start position. The ECM then supplies a ground to the control circuit of the starter relay. When this occurs, battery voltage is supplied through the switch of the starter relay through the closed PNP switch to the starter solenoid. On manual transmissions the clutch start switch interrupts the control circuit from the ECM to prevent the engine from cranking unless the clutch pedal is fully pressed.

### Conditions for Running the DTC

• | The Ignition is in the START position.

• | The system voltage is between 9.5-18 volts.

### Conditions for Setting the DTC

The UEC detects improper voltage on the control circuit of the starter relay.

### Action Taken When the DTC Sets

DTC B1428 sets as current in the UEC

### Conditions for Clearing the DTC

The DTC clears when the relay B+ or relay control circuit has repaired or a faulty starter relay has been replaced.

### Reference Information

#### Schematic Reference

Starting and Charging Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Starting System Description and Operation

#### 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. Ignition ON, verify that no power mode , clutch pedal, automatic transmission, serial data, or related UEC, SCCM , ECM DTCs are set.

⇒ | If other DTCs are set diagnosis those first.

### Circuit/System Testing

1. Verify that DTCs P0616 or P0617 are not set
2. Ignition ON, verify DTC B1428 is set as current.
3. Ignition OFF, disconnect the starter relay, test for 60-180 ohms between relay terminals 85 and 86.

⇒ | If not within the specified range, replace the starter relay.

4. Ignition ON, verify a test lamp illuminates between the relay coil supply voltage circuit terminal 86 and ground.

⇒ | If the test lamp did not illuminate , test the relay coil supply voltage circuit for a short to ground or an open/high resistance.

5. Ignition OFF, connect a test lamp between the relay coil supply voltage circuit terminal 86 and the relay control circuit terminal 85.
6. Fully depress clutch pedal on manual transmissions or PARK/Neutral on automatic transmissions.
7. Place the ignition to the start position.
8. The test lamp should only illuminate when the ignition is held in the start position.

⇒ | If the test lamp is always ON, test the control circuit for short to ground.

⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/ high resistance.

9. If the circuits test normal, replace the ECM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Relay Replacement

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