Volt

DTC P0AA6, P1AE6 or P1F0E

The vehicle is equipped with a high-voltage isolation monitor feature. The purpose of the battery energy control module high-voltage isolation monitor circuit is to test the resistance between the high- voltage positive and negative direct current (DC) bus and chassis earth. The battery energy control module isolation monitoring system measures the resistance between the high-voltage system and chassis earth in the following way. The battery energy control module places an AC signal on the high-voltage system and monitors its amplitude. A reduced amplitude return signal indicates a loss of resistance to chassis earth. This isolation monitor method is sometimes referred to as the active isolation monitor. The hpcm2 requests the BECM to perform this test. Measurement values are reported to the hpcm2 , which makes the determination of an isolation fault.

The isolation check for P0AA6 Hybrid Battery Voltage System Isolation Lost runs when all the contactors (main positive, main negative contactor, multi-purpose contactor, charger positive contactor and charger negative contactor) are open. This check monitors isolation in the drive motor battery system. This check runs only once during the time that the hpcm2 is awake and runs after the contactors have been open for 10 seconds. This monitor typically runs when the vehicle is turned off after a drive. It could also run when the vehicle is first started, if there is a long enough period between the hpcm2 waking up and the main contactors closing.

The isolation check for P1F0E Battery Charging Voltage System Isolation Lost runs when the main contactors and the multi-purpose contactor are open and the charger contactors are closed. This check monitors for isolation in the charger system along with the drive motor battery system. This check runs once during the time that the hpcm2 is awake and requires that the contactors main and multi-purpose contactors be open and the charger contactors be closed for 10 seconds.

The battery energy control module runs an internal self check of this sensor circuit. When this test fails, DTC P1AE6 will be set.

P0AA6

P1AE6

P1F0E

P0AA6

P1AE6

The battery energy control module has detected no return AC signal, thus indicating a fault with the active isolation sensing circuits.

P1F0E

DTCs P0AA6, P1AE6 and P1F0E are Type A DTCs.

Schematic Reference

Hybrid Energy Storage Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Battery System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-48900 HEV Safety Kit

For equivalent regional tools, refer to Special Tools .

1. Verify that the vehicle hybrid/EV battery cooling system is full.

⇒	If the hybrid/EV battery cooling system is low, refer to Hybrid/EV Battery Cooling Diagnostic .

2. Observe the scan tool hybrid powertrain control module 2, Isolation Test Resistance parameter. The reading should display greater than 500k Ω.

Danger: High voltage enabling and disabling shall be only performed by High Voltage Qualified Technicians. The procedures for high-voltage enabling/disabling can be found in the service instructions and must be strictly followed at all times. The usage of the Protocol High Voltage Disabling/Enabling is mandatory. The High-Voltage Qualified Technician is responsible for the adherence to the manufacturer's service instructions as well as current national legal regulations.

Danger: Any hybrid/EV battery pack replacement shall be performed by High-Voltage Qualified Technicians only. The replacement procedure can be found in the service instruction and must be strictly followed at all times. The High-Voltage Qualified Technician is responsible for adherence to the manufacturer's service instructions as well as current national legal regulations. If the hybrid/EV battery pack needs to be replaced contact the Technical Assistance Centre for further instructions prior to removal of the battery pack.

1. Vehicle OFF, disable the high voltage at the A4 hybrid/EV battery pack. Refer to High Voltage Disabling .
2. Connect the 12 V battery.
3. Vehicle in Service Mode, verify that DTC P0A7E, P0AA1, P0AD9, P0ADD, P0AE2, P0AE4, P0C32, P0D0A, P0D11, P1EBC-P1EBF, P1EC0 or P1EC3-P1EC5 is not set.

⇒	If any DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

4. Vehicle OFF, disconnect the 12 V battery.

Note: The following continuity tests must be performed using an Insulation Multimeter. Select the Isolation test setting, then select the 500 V range.

5. With the Insulation Multimeter, set on the Isolation test setting, test for greater than 400k Ω between the A28 hybrid battery contactor assembly harness connector terminals listed below and chassis earth:

•	Battery charger negative harness side terminal B X5

•	Battery charger positive harness side terminal A X5

⇒

If less than the specified range, disconnect the X4 connector at the T18 battery charger. Test for greater than 400k Ω between the circuit terminals and chassis earth. If the test result is greater than the specified value, replace the T18 battery charger. If the test result is less than the specified range, replace the 300 V DC cables and test or replace the charger fuse.

6. Remove the fuse cover and battery protector (Insulator). Refer to Battery Charger and 14 V Power Module Maxi 20 A Fuse Replacement .
7. With the Insulation Multimeter, set on Ohm setting, test for less than 1 Ω across the battery charger fuse.

⇒	If greater than the specified range, replace the battery charger fuse.

8. If all the circuit tests normal, replace the A4 hybrid/EV battery pack.

Perform the Diagnostic Repair Verification after completing the repair.