Diagnostic Instructions
DTC Descriptor
DTC B1428: Ignition Switched Power Run/Crank Relay Circuit
Diagnostic Fault Information
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
Run/Crank Ignition 1 voltage
| B 1428 00
| 1
| 2
| --
|
- No Start. SIR system will retain DTC B 1370 06 as current.
- Vehicle will start and continue to run after the ignition key is removed.
|
Circuit/System Description
The body control module (BCM) controls the R6 IGN relay through the run/crank ignition 1 voltage circuit by applying voltage to the circuit. The R6 IGN 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
Power Distribution Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
Circuit/System Testing
- Ignition OFF, disconnect the R6 IGN relay and connect a test lamp between the relay control circuit 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 remains OFF all the time, test for a short to ground or an open/high resistance on the relay control circuit. If the circuit tests normal, replace the BCM. |
⇒ | If the test lamp remains ON all the time, test for a short to voltage on the relay control circuit. If the circuit tests normal, replace the BCM. |
- If test lamp turns ON and OFF normal, test or replace the R6 IGN relay.
Component Testing
- Ignition OFF, disconnect the R6 IGN relay .
- Test for 70-150 ohms of resistance between terminals 85 and 86.
⇒ | If the resistance is not within the specified range, replace the relay. |
- Test for infinite resistance between the following terminals:
⇒ | If less than infinite resistance, replace the relay. |
- 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.
Control Module References for BCM replacement, setup, and programming