P1A0E
DTC P1A0E or P1A0F
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 Descriptors
DTC P1A0E
- Battery Energy Control Module Hybrid Battery Voltage Sensor Circuit Low Voltage
DTC P1A0F
- Battery Energy Control Module Hybrid Battery Voltage Sensor Circuit High Voltage
Circuit/System Description
The battery energy control module (BECM) monitors the link voltage for a low and high voltage condition.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
P1A0E
Pack voltage raw A/D less than 0.5 volt.
P1A0F
Pack voltage raw A/D greater than 4.5 volt.
Action Taken When the DTC Sets
Hybrid system is inactive.
Conditions for Clearing the DTC
Link voltage returns between the calibrated thresholds.
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.
Important: 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
P1A0E
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 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 the BECM.
4. Disconnect connectors X1 and X2 from the BECM.
5. Test for less than 6.5 volts between X1 terminal 1 and X2 terminal 1, while depressing the service disconnect switch.
• If greater than the specified range, replace the BECM.
6. Remove the generator battery cover. Refer to Generator Battery Temperature Sensor Replacement ().
7. 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.
8. Measure the resistance between X1 terminal 1 and ring terminal 7. Should measure 700-800 ohms.
• If not within specified range, replace the harness assembly.
P1A0F
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. Should read pack voltage.
3. Measure the voltage at ring terminal 1 to ground. Should read no voltage.
• If greater than the specified range, replace the BECM.
4. Disconnect connectors X1 and X2 from the BECM.
5. Remove the generator battery cover. Refer to Generator Battery Temperature Sensor Replacement ().
6. 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.
7. Measure the resistance between X1 terminal 1 and ring terminal 7. Should measure 700-800 ohms.
• If not within specified range, replace the harness assembly.
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