The hybrid drive motor battery contains 3 high voltage (HV) contactor relays that allow the HV DC batteries to be connected to the vehicle. The three relays are a positive HV contactor relay, negative HV contactor relay and the inverter current limit relay, also known as a precharge relay. These relays close and open in a certain sequence controlled by the battery energy control module (BECM). The control circuit for the relays use a common ground and the BECM provides 12 V to turn them on and removes 12 V to turn them off. The contactor relays are monitored by HV diagnostics in the BECM and the hybrid powertrain control module (HPCM). If any relay fails their diagnostic check, then the high voltage interlock circuit (HVIC) signal will not source HVIC current until the fault is repaired.

The current limit resistor for precharge is rated at 12 Ω. If approximately 12 Ω is measured across the X2 and X3 connectors at the positive contactor relay, the inverter current limit relay could be stuck closed.

When DTC P0C76 is set, you must use the scan tool Special Functions feature, under the Battery Energy Control Module data list after the repair is complete.

Electrical Information Reference

Special Tools

Danger: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.

The High Voltage Disabling procedure will perform the following tasks:

•	Identify how to disable high voltage.

•	Identify how to test for the presence of high voltage.

•	Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.

Failure to follow the procedures exactly as written may result in serious injury or death.
1. Ignition ON, observe the scan tool Contactor System Status parameter. The reading should be Closed.
2. Ignition OFF, after the relay contactors click open, observe the scan tool Contactor System Status parameter. The reading should be Open.
3. Ignition OFF, observe the scan tool Hybrid Battery Terminal parameter. The reading should be less than 15 V.
4. Perform the High Voltage Disabling procedure and identify if a loss of isolation or a stuck closed contactor condition is present.

⇒	If a loss of isolation condition was identified, refer to Loss of Isolation Diagnosis.

⇒	If a stuck closed contactor was identified, refer to HV Negative Contactor Relay Diagnosis or HV Positive and Inverter Current Limit Relay Diagnosis.

Loss of Isolation Diagnosis

Danger: Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:

•	Safety glasses with appropriate side shields when within 50 feet of the vehicle, either indoors or outdoors

•	Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors

-	Visually and functionally inspect the gloves before use.

-	Wear the Insulation gloves at all times when working with the high voltage battery assembly, whether the system is energized or not.

Failure to follow the procedure exactly as written may result in serious injury or death.

Danger: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.

The High Voltage Disabling procedure will perform the following tasks:

•	Identify how to disable high voltage.

•	Identify how to test for the presence of high voltage.

•	Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.

Failure to follow the procedures exactly as written may result in serious injury or death.

Important: This diagnosis for loss of isolation should only be followed if you were sent here from test results identified by performing the high voltage disabling procedure.

1. Remove the drive motor generator battery case upper cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement.
2. Visually inspect the high voltage DC cables internal to the drive motor generator battery. Verify there is no damage or short to chassis ground.

⇒	If any of the high voltage (HV) cables are damaged or grounded, replace the HV cables as necessary.

3. If all circuits test normal, replace the GBCM.

HV Negative Contactor Relay Diagnosis

Danger: Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:

•	Safety glasses with appropriate side shields when within 50 feet of the vehicle, either indoors or outdoors

•	Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors

-	Visually and functionally inspect the gloves before use.

-	Wear the Insulation gloves at all times when working with the high voltage battery assembly, whether the system is energized or not.

Failure to follow the procedure exactly as written may result in serious injury or death.

Danger: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.

The High Voltage Disabling procedure will perform the following tasks:

•	Identify how to disable high voltage.

•	Identify how to test for the presence of high voltage.

•	Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.

Failure to follow the procedures exactly as written may result in serious injury or death.
1. Verify DTC P0C76 is not set.

⇒	If DTC P0C76 is set, replace the inverter current limit relay, HV positive and HV negative contactor relays.

2. Remove the drive motor generator battery upper cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement.
3. Test for infinite resistance across the high voltage negative contactor relay X2 and X3 terminal connections.

⇒	If less than the specified value, replace the HV negative contactor relay.

Important: If the HV contactor relays opened while under high current load, replace BOTH HV contactor relays. The following conditions could cause the HV contactor relays to open while under high current load:

•	A collision resulting in supplemental inflatable restraint (SIR) deployment.

•	A collision that activates the high voltage circuit impact detection (HVCID) sensor.

•	A HVCID sensor circuit fault that occurs while the vehicle is moving.

•	A loss of power or ground to the BECM while the vehicle is moving.

⇒	If the HV contactor relays opened while under high current load, replace both the HV positive and HV negative contactor relays.

4. Disconnect the inline connector at the HV negative contactor relay.
5. Connect the 12 V battery.
6. Connect a test lamp between negative contactor relay harness connector terminal 1 and ground. The test lamp should not illuminate.

⇒	If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the BECM.

7. If all circuits test normal, test or replace the HV negative contactor relay.

HV Positive and Inverter Current Limit Contactor Relay Diagnosis

Danger: Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:

•	Safety glasses with appropriate side shields when within 50 feet of the vehicle, either indoors or outdoors

•	Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors

-	Visually and functionally inspect the gloves before use.

-	Wear the Insulation gloves at all times when working with the high voltage battery assembly, whether the system is energized or not.

Failure to follow the procedure exactly as written may result in serious injury or death.

Danger: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.

The High Voltage Disabling procedure will perform the following tasks:

•	Identify how to disable high voltage.

•	Identify how to test for the presence of high voltage.

•	Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.

Failure to follow the procedures exactly as written may result in serious injury or death.
1. Verify if DTC P0C76 was set.

⇒	If DTC P0C76 was set, replace the inverter current limit relay, HV positive and HV negative contactor relays.

2. Remove the drive motor generator battery upper cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement.
3. Test for infinite resistance across the positive high voltage contactor relay X2 and X3 terminal connections.

⇒	If less than the specified value, disconnect the X3 connector from terminal 1 on the inverter current limit relay and continue with diagnosis.

4. Test for infinite resistance across the positive high voltage contactor relay X2 and X3 terminal connections.

⇒	If less than the specified value, replace the HV positive contactor relay.

Important: If the HV contactor relays opened while under high current load, replace BOTH HV contactor relays. The following conditions could cause the HV contactor relays to open while under high current load:

•	A collision resulting in supplemental inflatable restraint (SIR) deployment.

•	A collision that activates the high voltage circuit impact detection (HVCID) sensor.

•	A HVCID sensor circuit fault that occurs while the vehicle is moving.

•	A loss of power or ground to the BECM while the vehicle is moving.

⇒	If the HV contactor relays opened while under high current load, replace both the HV positive and HV negative contactor relays.

5. Test for infinite resistance across the current limit relay between terminals 1 and 2.

⇒	If less than the specified value, replace the inverter current limit relay.

6. Connect the 12 V battery.
7. Disconnect the inline connector at the HV positive contactor relay.
8. Connect a test lamp between the positive contactor relay harness connector terminal 1 X1 and ground. The test lamp should not illuminate.

⇒	If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the BECM.

9. Connect a test lamp between inverter current limit relay connector terminal 5 X1 and ground. The test lamp should not illuminate.

⇒	If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the BECM.

10. If all circuits test normal, test or replace the HV positive contactor relay and the current limit relay.

Contactor Relay Test

Danger: Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:

•	Safety glasses with appropriate side shields when within 50 feet of the vehicle, either indoors or outdoors

•	Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors

-	Visually and functionally inspect the gloves before use.

-	Wear the Insulation gloves at all times when working with the high voltage battery assembly, whether the system is energized or not.

Failure to follow the procedure exactly as written may result in serious injury or death.
1. Ignition OFF, perform the high voltage disable procedure. Refer to High Voltage Disabling.
2. Remove the drive motor generator battery upper cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement.
3. Disconnect inline connector at the HV positive contactor relay, or the inline connector at the HV negative and positive contactor relays.
4. With a DMM measure between 20-30 Ω between terminals 1 and 2 at the connector on the component harness side.

⇒	If the value is not within the specified range, replace the HV relay contactor.

5. Disconnect inline connectors X1 and X2 at the inverter current limit relay.
6. With a DMM measure between 55-75 Ω between terminals 5 and 6 at the inverter current limit relay.

⇒	If the value is not within the specified range, replace the inverter current limit relay.

Note: If you are preparing the drive motor generator battery for shipment, Install the terminal extension cover assembly and retaining bolts. Using UL® listed or equivalent insulation tape rated at a minimum of 600 V, tape over the manual disconnect opening and the HV cable openings on the terminal extension cover. Remove the drive motor battery assembly, refer to Drive Motor Generator Battery Replacement.

Perform the Diagnostic Repair Verification after completing the repair.