B144A
DTC B144A
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC B144A 01
- Run Power Relay Circuit Short to Battery
DTC B144A 02
- Run Power Relay Circuit Short to Ground
DTC B144A 04
- Run Power Relay Circuit open
Diagnostic Fault Information
Circuit/System Description
The Body Control Module (BCM) controls the Ignition Run Relay through the control circuit by applying voltage to the Auxiliary Ignition Run Relay coil control circuit. The Ignition Run Relay is energized when the ignition is in the ACCESSORY or ON positions.
Conditions for Running the DTC
* The system voltage is between 9-16 V.
* The DTC can only run when the output is activated.
Conditions for Setting the DTC
B144A 01
The ignition output is not active and a short to battery is detected 3 consecutive times on the ignition voltage circuit.
B144A 02
A short to ground is detected on the Ignition Run Relay coil control circuit.
B144A 04
The ignition output is not active and an open is detected 20 consecutive times on the ignition voltage circuit.
Action Taken When the DTC Sets
B144B 01, B144B 04
No action is taken.
B144B 02
The module output driver will be shut down and not supply voltage to the Ignition Run Relay control 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.
Reference Information
Schematic Reference
Power Moding Schematics Power Moding Schematics
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
Description and Operation
Power Mode Description and Operation Power Mode
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the KR74 Ignition Run Relay turns ON and OFF when commanding the Run Relay On and Off with a scan tool.
• If the KR74 Ignition Run Relay does not turn ON and OFF
Refer to Circuit/System Testing
• If the KR74 Ignition Run Relay turns ON and OFF
3. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect the KR74 Ignition Run Relay, ignition ON.
2. Connect a test lamp between the control circuit terminal 86 and ground.
3. Verify the test lamp turns ON and OFF when commanding the Run Relay On and Off with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K9 Body Control Module.
• If the test lamp is always ON
1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON.
2. 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
4. Test or replace the KR74 Ignition Run Relay.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)
* Control Module References Control Module References for the Body Control Module replacement, programming and setup