Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P1A07: Buffered +5V Out of RangeCircuit/System Description
The battery energy control module (BECM) monitors the internal +5V reference for a out of range condition.
Conditions for Running the DTC
The engine is running, and the 12V input l to the BECM is greater than 9 volts.
Conditions for Setting the DTC
The BECM detects the internal +5V reference circuit is less than 4.7 volts for greater than 3.7 seconds.
Action Taken When the DTC Sets
The DTC sets, does not affect hybrid operation.
Conditions for Clearing the DTC
The BECM detects the internal +5V reference circuit is greater than 4.7 volts.
Reference Information
Schematic Reference
Hybrid Energy Storage Schematics
Connector End View Reference
Description and Operation
Generator Battery Carrier Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Special Tools
J 35616 GM Approved Terminal Test Kit
Circuit/System Verification
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 generator battery disconnect control module. Internal components will still be live, 36V potential, even when the cover has been opened or removed.
Note: Use the following list to identify the appropriate terminals to test:
| • | J-35616-65B for female terminals |
| • | J-35616-64B for male terminals |
If the DTC occurs with P0AC0, P0AC1, P1A48 then the failure this diagnostic detects may have been the root cause of other current sensor DTCs that may have set.
Circuit/System Testing
- Verify the DTC is set as current. If other DTCs are set diagnose those first.
- Disconnect BECM X1. Refer to Hybrid Battery Service Disconnect/Connect.
- Disconnect the current sensor harness.
- Test for greater than 100k ohms between terminals 9 and 10.
- Test for less than 1.0 ohm between terminal 9 and terminal B and between terminal 10 and D.
- If the circuits test normal, replace the BECM.
| ⇒ | If less than specified value, replace the harness. |
| ⇒ | If greater than specified value, replace the harness. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for BECM replacement, setup, and programming
