Diagnostic Instructions
DTC Descriptor
DTC P0AC0: Hybrid Battery Current Sensor Performance
Circuit/System Description
The generator battery disconnect control module monitors for the following:
| • | Golden range check, ensures the zero point for both current sensors is set within a good range. |
| • | Correlation check, ensures that the difference between the two sensors is 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
Hybrid Energy Storage Connector End Views
Electrical Information Reference
Scan Tool Reference
Scan Tool Data List
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 the generator battery disconnect control module C1 and C2 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 |
- Verify that the DTC is set as current.
| ⇒ | If the DTC is history refer to Testing for Intermittent Conditions and Poor Connections. |
- Disconnect harness connector C1 at the generator battery disconnect control module. Refer to
Hybrid Battery Service Disconnect/Connect.
- Disconnect current sensor harness.
- Test for less than 1 ohm of resistance between the following circuits.
| • | C1 terminal 20 to current sensor connector terminal A |
| • | C1 terminal 9 to current sensor connector terminal B |
| • | C1 terminal 19 to current sensor connector terminal C |
| • | C1 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 / generator battery disconnect control module.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
