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 02
- Run Power Relay Circuit Short to Ground

Diagnostic Fault Information






Circuit/System Description

The body control module (BCM) feeds the ignition circuit by applying voltage when the vehicle is in the Ignition ON mode.

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

The BCM detects a short to ground in the ignition circuit.

Action Taken When the DTC Sets

The module output driver will be shut down and not supply voltage to the ignition 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

HVAC Schematics HVAC - Automatic

Connector End View Reference

Component Connector End Views Sunshade - Left

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 Testing

1. Ignition OFF, disconnect the X2 harness connector at the K33 HVAC control module.

2. Connect a test lamp between the ignition circuit terminal 9 and ground.

3. Verify the test lamp turns ON and OFF when cycling the S38 Ignition Mode Switch between Ignition ON and Ignition OFF.

• If the test lamp is always OFF

1. Ignition OFF remove the test lamp.

2. Test for infinite resistance between the ignition 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 ignition 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, remove the test lamp.

2. Test for less than 1 V between the ignition 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 K33 HVAC control module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)

* Control Module References Control Module References for body control module or HVAC control module replacement, programming and setup