B151B

DTC B151B

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 B151B
- Current Sensor Polarity Error - GBCM

Circuit/System Description

The generator battery control module (GBCM) monitors its internal battery current sensor for many charging system operations, and also for diagnostic purposes. If reversed polarity of the battery current is sensed, then DTC B151B will set.

Conditions for Running the DTC

* The engine is not running.
* DTC B1516 is not set.

Conditions for Setting the DTC

The GBCM detects positive battery current.

Action Taken When the DTC Sets

The regulated voltage control (RVC) is disabled.

Conditions for Clearing the DTC

The GBCM detects correct polarity of the battery current.

Diagnostic Aids

DTC B151B may set if a battery charger is used.

Reference Information
Schematic Reference

Starting and Charging Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Charging System 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 (Programming and Relearning)for scan tool information

Circuit/System Verification

1. Verify that the GBCM is installed correctly. The GBCM should be installed on the negative battery cables, with the sensor coil around the negative cables and facing away from the battery, and with the harness connector facing toward the battery.

• If the GBCM is installed backwards or incorrectly, remove and reinstall the GBCM.

2. Ignition ON, clear the DTC with the scan tool. Verify that DTC B151B does not set.

• If the DTC sets, replace the GBCM.

Repair Instructions

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

Control Module References (Programming and Relearning)for GBCM replacement, setup, and programming.