Diagnostic Instructions
DTC Descriptor
DTC P0AC0: Hybrid Battery Current Sensor Performance
Circuit/System Description
The battery energy control module (BECM) monitors for the following:
| • | Golden range check, ensures the zero point for both current sensors are set within a valid range. |
| • | Correlation check, ensures that the difference between the two sensors are not too large. |
| • | Polarity check, ensures that the pack voltage and pack current are tracking each other. |
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
| • | Golden range check fault: |
| - | Low range zero point raw A/D is outside of 2.5 volts +/- 0.7 percent. |
| - | High range zero point raw A/D is outside of 3.3 volts +/- 1 percent. |
| • | Correlation check fault: The absolute value (current sensor 1 - current sensor 2) is greater than 5 amps. |
| - | In Charge, pack voltage final is less than pack voltage initial -1 volt after 1 second. |
| - | In Discharge, pack voltage final is greater than pack voltage initial +1 volt after 1 second. |
Action Taken When the DTC Sets
Hybrid system is disabled.
Conditions for Clearing the DTC
| • | Golden range check fault: |
| - | Current sensor DTCs = PASSED. |
| - | Contactor command = transition to CLOSED. |
| • | Correlation check fault: |
| - | Current sensor DTCs = PASSED. |
| - | Current Sensor 1 and 2 = VALID. |
| - | -30 amps is less than current sensor 1 and is less than 30 amps. |
| - | -350 amps is less than current sensor 2 and is less than 150 amps. |
| - | Pack and module voltages = VALID. |
| - | Current sensor DTCs = PASSED. |
| - | Pack and module DTCs = PASSED. |
| - | Pack current is greater than 50 amps or pack current is less than -50 amps. |
Reference Information
Schematic Reference
Hybrid Energy Storage Schematics
Connector End View Reference
Component Connector End Views
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 Testing
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.
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.
Important: Use the following list to identify the appropriate terminals to test:
| • | J-35616-65B for female terminals |
| • | J-35616-64B for male terminals |
- Verify that the DTC is set as current.
- Disconnect harness connector X1 for the BECM. Refer to
Hybrid Battery Service Disconnect/Connect.
- Disconnect current sensor harness.
- Test for less than 1 ohm between the following circuits.
| • | X1 terminal 20 to current sensor connector terminal A |
| • | X1 terminal 9 to current sensor connector terminal B |
| • | X1 terminal 19 to current sensor connector terminal C |
| • | X1 terminal 10 to current sensor connector terminal D |
| ⇒ | If greater than specified value, replace the current sensor harness assembly. |
- If all circuits test normal, replace the current sensor / BECM.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for BECM replacement, setup, and programming
