P1A4E
DTC P1A4E
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 Descriptor
DTC P1A4E
- Battery Energy Control Module Hybrid Battery System Voltage High
Circuit/System Description
The battery energy control module (BECM) monitors the hybrid battery system for an over voltage condition. A diagnostic is running continuously to verify that the generator battery voltage is not above 52 V. DTC P1A4E will set if the diagnostic detects that the voltage is above 52 V.
Conditions for Running the DTC
The ignition is in the RUN position.
Conditions for Setting the DTC
Generator battery voltage greater than 52 V.
Action Taken When the DTC Sets
Does not affect hybrid system operation
Conditions for Clearing the DTC
Generator battery voltage returns to normal operating range.
Reference Information
Schematic Reference
Hybrid Energy Storage Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Generator Battery Carrier 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
Special Tools
J 35616 GM Approved Terminal Test Kit
Circuit/System Testing
Warning
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.
Warning
To help avoid personal injury, be careful when working in the vicinity of the battery energy control module. Internal components will still be live, 36V potential, even when the cover has been opened or removed.
Note: In order to avoid damaging BECM X1 and X2 connector terminals, the proper test probes should be used. The proper test probes are as follows:
* J-35616-65B for female terminals
* J-35616-64B for male terminals
1. Verify the DTC is set as current.
• If the DTC is history, refer to Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections).
2. Scan and record the generator battery voltage.
3. Measure the voltage between ring terminal 3 and ground. Should read less than 52 V. Refer to Hybrid Battery Service Disconnect/Connect (Procedures).
• If greater than the specified value, replace the generator battery.
4. Disconnect harness connector X1 from the BECM.
5. Test for 1.3-1.7k ohm between the following circuits:
* X1 terminal 1 to Generator Battery 1-X1
* X1 terminal 11 to Generator Battery 1-X2
* X1 terminal 2 to Generator Battery 2-X2
* X1 terminal 12 to Generator Battery 3-X2
• If not within specified range, replace the voltage sensor harness assembly.
6. If all circuits test normal, replace the BECM.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Generator Battery Replacement (Generator Battery Replacement)
* Generator Battery Temperature Sensor Wiring Harness Replacement (Generator Battery Temperature Sensor Wiring Harness Replacement)
* Control Module References (Programming and Relearning) for BECM replacement, programming and setup