B1566

DTC B1566

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B1566
- Current Sensor Polarity Check

Circuit/System Description

The generator battery control module (GBCM) monitors its internal battery current sensor for many charging system operations. When the polarity of the battery current is sensed, DTC B1566 will set.

Conditions for Running the DTC

* The engine is running.
* This diagnostic runs every 50 ms.

Conditions for Setting the DTC

The duty cycle of the internal battery current sensor is less than 2 percent duty cycle or greater than 98 percent duty cycle for 240 seconds.

Action Taken When the DTC Sets

* The charge indicator turns ON.
* The driver information center (DIC) displays the BATTERY message.
* The filtered battery current is set to 0.1 amp.
* The generator field control circuit duty cycle is set to 100 percent, battery voltage defaults to 13.8 volts.

Conditions for Clearing the DTC

The duty cycle of the internal battery current sensor is greater than 2 percent duty cycle or less than 98 percent duty cycle.

Diagnostic Aids

You must cycle the ignition after clearing the DTC to turn OFF the BATTERY DIC message.

Circuit/System Verification

1. Verify that DTC B1566 is set as current.

^ If the DTC is history, refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. Component Tests and General Diagnostics

2. Ignition ON, clear the DTC using the scan tool and start the engine.

^ If the DTC resets, replace the GBCM.

Repair Instructions

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