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: Ignition Switched Power Relay 1 CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Run/Crank Ignition 1 Voltage | B1428 00 | 1 | 2 | -- |
1. No Start. SIR system will retain DTC B1370 06 as current. 2. Vehicle will start and continue to run after the ignition key is removed. | ||||
Circuit/System Description
The body control module (BCM) controls the Run/Crank relay through the run/crank ignition 1 voltage circuit by applying voltage to the circuit. The Run/Crank relay is energized when the ignition switch is in ON or START, or when a remote start is requested.
Conditions for Running the DTC
| • | The system voltage is between 9-16 volts. |
| • | The DTC can only run when the output is activated. |
Conditions for Setting the DTC
The DTC will set only when the output is activated and there is a short to ground in the run/crank ignition 1 voltage circuit.
Action Taken When the DTC Sets
The module output driver will be shut down and not supply voltage to the run/crank ignition 1 voltage circuit.
Conditions for Clearing the DTC
| • | The current DTC will clear when the module request for the output is removed or the malfunction is no longer present. |
| • | A history DTC clears when the module ignition cycle counter reaches the reset threshold of 50, without a repeat of the malfunction. |
Diagnostic Aids
| • | Use the DMM MIN/MAX function to capture/locate intermittent conditions. |
| • | Short to voltage in the run/crank ignition 1 voltage circuit will cause the malfunction indicator lamp (MIL) to illuminate with the ignition key OFF, and the engine will remain running if started and the ignition key is removed. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Power Mode Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the Run/Crank relay.
- Connect a test lamp between the relay coil control circuit terminal and ground.
- Cycle the ignition ON and OFF. The test lamp should turn ON and OFF when changing ignition switch positions.
- If the test lamp illuminates normal, test or replace the Run/Crank relay.
| ⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
| ⇒ | If the test lamp is always OFF, test the control circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the BCM. |
Component Testing
- Ignition OFF, disconnect the Run/Crank relay.
- Test for 70-150 ohms of resistance between terminals 85 and 86.
- Test for infinite resistance between the following terminals:
- Install a 3-amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Measure for less than 5 ohms of resistance between terminals 30 and 87.
| ⇒ | If the resistance is not within the specified range, replace the relay. |
| • | 30 and 86 |
| • | 30 and 87 |
| • | 30 and 85 |
| • | 85 and 87 |
| ⇒ | If less than specified, replace the relay. |
| ⇒ | If greater than specified, replace the relay. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Refer to Control Module References for BCM replacement, setup, and programming
