B151D

DTC B151D

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 B151D 03
- Control Module Power Circuit Low Voltage

DTC B151D 07
- Control Module Power Circuit High Voltage

Circuit/System Description

The body control module (BCM) monitors the low precision battery voltage to the BCM. Damage to components, and incorrect data may occur when the voltage is out of range.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

* Ignition ON, engine running idle.

* The BCM detects a supply voltage lower than 6 V.

* The BCM detects a supply voltage greater than 18 V.

Action Taken When the DTC Sets

* A driver information center message and/or warning indicator may be displayed.

* The control module may be disabled while a low or high DTC is current.

Conditions for Clearing the DTC

The supply voltage returns to the normal operating range.

Diagnostic Aids

* A low or high voltage DTC set in multiple modules may indicate a concern with the charging system.

* A possible cause of the high voltage DTC could be overcharging with a battery charger, jump starting or a generator malfunction.

Reference Information

Schematic Reference

Body Control System Schematics [1][2]Body Control Systems for control module schematics

Connector End View Reference

Component Connector End Views Fuel Pump and Level Sensor Assembly

Description and Operation

* Charging System Description and Operation Description and Operation

* Battery Description and Operation Description and Operation

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

Note: Some control module ground circuits may require up to 20 min after the ignition is turned off before achieving a resistance reading of less than 5 ohms. In most cases the readings will drop below 20 ohms between 1 min indicating the control module is going to sleep.

1. Ignition OFF and all vehicle systems OFF, disconnect all harness connectors at the K9 Body Control Module. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 10 ohms between each ground circuit terminal and ground.

• If 10 ohms or greater

1. Ignition OFF.

2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, repair the open/high resistance in the ground connection.

• If less than 10 ohms

3. Reconnect all harness connectors to the K9 Body Control Module, except X2

4. Ignition ON, engine running idle

5. Test for more than 6 V and less than 18 V between terminal 1 X2 and ground.

• If less than 6 V and the circuit fuse is good

1. Ignition OFF.

2. Test for less than 2 ohms in battery positive voltage circuit terminal 1, X2 end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.

• If less than 6 V and the circuit fuse is open

1. Ignition OFF.

2. Test for infinite resistance between battery positive voltage circuit terminal 1, X2 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the K9 Body Control Module.

• If 18 V or greater

1. Ignition OFF.

2. Refer to Charging System Test Testing and Inspection.

• If between 6-18 V and DTC is set

6. 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 for control module replacement, programming and setup