P1A47

DTC P1A47

Diagnostic Instructions

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



DTC Descriptor
DTC P1A47
- Battery Energy Control Module Hybrid Battery Voltage Sensor Performance




Circuit/System Description

The battery energy control module (BECM) monitors the link voltage performance. If any voltage is off, this DTC will set.


Conditions for Running the DTC

The engine is running.


Conditions for Setting the DTC

Absolute value (Link voltage - sum of all module voltages) is greater than 5 volts.


Action Taken When the DTC Sets

Does not affect Hybrid Operation.


Conditions for Clearing the DTC

The difference between the link voltage and the sum of pack voltages decrease below threshold.


Reference Information
Schematic Reference

Hybrid Energy Storage Schematics ()
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for Scan Tool Information
Special Tools

J 35616 GM Approved Terminal Test Kit


Circuit/System Testing

Caution: To help avoid personal injury, additional precautions must be taken prior to working on the generator control module or the generator starter. After removing the 36V battery cables from the generator battery, remove both engine wiring harness connectors from the generator control module. Wait at least 5 minutes and then remove the generator control module cover. Verify voltage levels at all 36V, 12V, and 3-phase connections, are less than 3 volts using a DMM before proceeding.


Caution: To help avoid personal injury, be careful when working in the vicinity of the generator battery disconnect control module. Internal components will still be live, 36V potential, even when the cover has been opened or removed.


* J-35616-65B for female terminals
* J-35616-64B for male terminals


1. Remove the generator battery disconnect control module cover. Refer to Hybrid Battery Service Disconnect/Connect ()
2. Measure and record the voltage at ring terminal 3 to ground.
3. Depress and hold the service disconnect switch for 20 seconds and measure the voltage at ring terminal 1 to ground. The voltage should read the same as in step 2.

• If no voltage was measured at ring terminal 1 with service disconnect switch depressed, replace BECM.

4. Disconnect harness connector X2 from the BECM.
5. Measure the resistance between X2 terminal 1 and ring terminal 1. Should measure 700-800 ohms.

• If not within specified range, replace the harness assembly.

6. If all circuits tests normal, replace BECM.



Repair Instructions

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


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