B1428

DTC B1428

DTC DESCRIPTOR
DTC B1428: Ignition Switched Power Run/Crank Relay Circuit

DIAGNOSTIC FAULT INFORMATION
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

CIRCUIT/SYSTEM DESCRIPTION
The body control module (BCM) controls the Run/Crank relay by applying voltage to the circuit. The Run/Crank relay is energized when the ignition switch is in RUN 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
DTC will set when the output is activated and there is a short to ground in the 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.

CIRCUIT/SYSTEM TESTING
1. Ignition OFF, disconnect the Run/Crank relay.
2. Connect a test lamp between the relay control circuit and ground.
3. Cycle the ignition ON and OFF. The test lamp should turn ON and OFF when changing ignition switch positions.
- 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 an open/high resistance. If the circuit tests normal, replace the BCM.
4. If all circuits test normal, test or replace the Run/Crank relay.

COMPONENT TESTING
1. Ignition OFF, disconnect the Run/Crank relay.
2. Test for 70-150 ohms of resistance between terminals 85 and 86.
- If the resistance is not within the specified range, replace the relay.
3. Test for infinite resistance between the following terminals:
- 30 and 86
- 30 and 87
- 30 and 85
- 85 and 87
4. Test for less then 2 ohms of resistance between terminals 30 and 87A.
- If greater then the specified range, replace the relay.
5. 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 2 ohms of resistance between terminals 30 and 87.
- If greater than 2 ohms, replace the relay.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the repair. Verification Tests
Control Module References for control module replacement, setup, and programming. Programming and Relearning