Diagnostic Instructions
DTC Descriptor
- DTC B1448 02
 Accessory Power Relay Circuit Short to Ground
Diagnostic Fault Information
Circuit  | Short to Ground  | Open/High Resistance  | Short to Voltage  | Signal Performance  | 
|---|
Relay Coil Control  | B1448 02  | 1  | 1  | —  | 
1. Retained Accessory Power Malfunction  | 
Circuit/System Description
The body control module (BCM) controls the retained accessory power relay through the control circuit by applying voltage to the retained accessory power relay coil control circuit. The retained accessory power relay is energized when the ignition switch is in the ACCESSORY or the ON position.
Conditions for Running the DTC
- The system voltage is between 9–16 V.
 - The DTC can only set when the output is actively being requested by the module.
 
Conditions for Setting the DTC
The DTC will set only when the module requests the output and there is a short to ground in the ignition voltage circuit.
Action Taken When the DTC Sets
The module output driver will be shut down and not supply voltage to the circuit.
Conditions for Clearing the DTC
- The current DTC will clear when 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.
 
Reference Information
Schematic ReferencePower Distribution Schematics
Connector End View ReferenceMaster Electrical Component List
Description and OperationRetained Accessory Power Description and Operation
Electrical Information ReferenceScan Tool ReferenceControl Module References for scan tool information
Circuit/System Verification
- Ignition ON.
 - Verify the KR76 retained accessory power relay turns ON and OFF when commanding the accessory/retained accessory power relay ON and OFF with a scan tool.
 - If the KR76 retained accessory power relay turns ON and OFF
 
- All OK.
 
Circuit/System Testing
- Ignition OFF, disconnect the KR76 retained accessory power relay, ignition ON.
 - Connect a test lamp between the control circuit terminal 86 and ground.
 - Verify the test lamp turns ON and OFF when commanding the accessory/retained accessory power relay ON and OFF with a scan tool.
 - If the test lamp is always OFF
 
- Ignition OFF, disconnect the harness connector at the K9 body control module.
 - Test for infinite resistance between the control circuit and ground.
 - If less than infinite resistance, repair the short to ground on the circuit.
 
- Test for less than 2 Ω in the control circuit end to end.
 - If 2 Ω or greater, repair the open/high resistance in the circuit.
 - If less than 2 Ω, replace the K9 body control module.
 
- If the test lamp is always ON
 
- Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.
 - Test for less than 1 V between the control circuit and ground.
 - If 1 V or greater, repair the short to voltage on the circuit.
 - If less than 1 V, replace the K9 body control module.
 
- If the test lamp turns ON and OFF
 
- Test or replace the KR76 retained accessory power relay.
 
Repair Instructions
Perform the  Diagnostic Repair Verification after completing the repair.