B1451

DTC B1451

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 Descriptors
DTC B1451 01
- Accessory Power Circuit Short to Voltage

DTC B1451 02
- Accessory Power Circuit Short to Ground

DTC B1451 04
- Accessory Power Circuit Open/High Resistance

Diagnostic Fault Information






Circuit/System Description

The keyless entry control module provides backup control for the accessory wakeup serial data circuit by applying voltage to the circuit. The accessory wakeup serial data circuit is energized when the ignition mode switch is in ACC or RUN.

Conditions for Running the DTC

B1451 01, B1451 04
* Vehicle power mode is OFF or Crank Request.
* Module is awake.
* DTC B1451 not already set.
* System voltage is 6-16 V.

B1451 02
* Vehicle power mode is ACC or RUN.
* Module is awake.
* Output is active.
* DTC B1451 is not already set.
* System voltage is 6-16 V.

Conditions for Setting the DTC

B1451 01

Accessory output is not active and a short to battery is detected 3 consecutive times.

B1451 02

Accessory output is active and a short to ground is detected 3 consecutive times.

B1451 04

Accessory output is not active and an open circuit is detected 20 consecutive times.

Action Taken When the DTC Sets

B1451 02

The accessory output is deactivated when a short to ground is detected. After 100 ms the output is activated again. This happens 3 times and then the output is deactivated until a new accessory request is received.

B1451 01, B1451 04

No action is taken.

Conditions for Clearing the DTC

* The current DTC will clear when the malfunction is no longer present during a DTC check.
* A history DTC clears after 40 malfunction-free ignition cycles.

Diagnostic Aids

* A short to voltage on the accessory wakeup serial data circuit will keep the vehicle serial data bus awake, which can drain the vehicle's battery.
* If DTC B1451 02 is set, be sure to test the accessory wakeup serial data circuit for a short to ground between the body control module (BCM) and each of the modules that receive a signal from the accessory wakeup circuit before replacing the BCM. A short to ground between the BCM and modules may provide feedback through the BCM to the keyless entry control module and result in the setting of the DTC.

Reference Information
Schematic Reference

* Body Control System Schematics [1][2]Body Control Systems
* Power Distribution Schematics Power Distribution Schematics

Connector End View Reference

Component Connector End Views Sunshade - Left (D6I)
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

Circuit/System Testing

1. Verify DTC B1330 is not set.

• If the DTC is set, refer to DTC B1325, B1330, B1517, C0800, P0560, P0562, or P0563 B1325.

2. Ignition OFF, disconnect the X2 harness connector at the K84 keyless entry control module.
3. Verify that a test lamp illuminates between B+ circuit terminal 5 and ground.

• If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. If the B+ fuse is open, test the B+ circuit for a short to ground.

4. Connect the X2 harness connector at the K8 keyless entry control module. Disconnect the X3 harness connector at the K 9 BCM.
5. Ignition OFF, test for less than 1 V between the ignition circuit terminal 5 and ground.

• If greater than the specified range, test the ignition circuit for a short to voltage. If the circuit tests normal, replace the K84 keyless entry control module.

6. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 5 and ground.

• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K84 keyless entry control module.

7. If all circuits test normal, replace the K9 body control module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

Control Module References Control Module References