P0ABB

DTC P0ABB

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 Descriptor

DTC P0ABB
- Hybrid Battery Voltage Sensor Performance

Circuit/System Description

The engine control module (ECM) performs a rationality check for the voltage sensor located in the battery energy control module (BECM) by comparing the pack power electronics bus, and module voltages. If the SGCM diagnostic causes the contactor open, this DTC could set falsely.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

* Battery Pack Voltage - Pack Rationality Mean Voltage is greater than 2 volts.
* Pack Rationality Mean Voltage = (Power Electronics Voltage + ModVolt 1 + ModVolt 2 + ModVolt 3) / 2

Action Taken When the DTC Sets

Hybrid system is inactive.

Conditions for Clearing the DTC

Voltage difference between the battery pack and the average of the battery pack and the power electronics bus returns below the calibrated threshold.

Diagnostic Aids

If the SGCM diagnostic causes the contactor open, this DTC could set falsely.

Possible 36 volt open circuit between starter/generator control module (SGCM) and BECM.

Special Tools

J 35616 GM Approved Terminal Test Kit

Circuit/System Testing

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.

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

1. If other DTCs are set diagnose those first.
2. If the DTC is still set as current and the contactor status is closed.
3. Scan and record the total pack and module voltages.
4. Remove the generator battery disconnect control module cover.
5. Measure the 1, 2, 3 module voltages and then the total pack voltage.

^ If any measured voltages differ than 0.5 volt than the scanned voltage, test the voltage sensing harness for a short or an open/high resistance.

6. Disconnect BECM connector X1.
7. Test for 1400-1800 ohms between the following circuits.

* X1 terminal 12 and Generator Battery 3-X2
* X1 terminal 2 and Generator Battery 2-X2
* X1 terminal 11 and Generator Battery 1-X2
* X1 terminal 1 and Generator Battery 1-X1

^ If not within specified range, replace the voltage sensing harness assembly.

8. If all circuits tests normal, replace BECM.

Repair Instructions

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

* Generator Battery Temperature Sensor Wiring Harness Replacement