P0AE7
DTC P0AE7
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 P0AE7
- Hybrid Battery Pre-charge Contactor Control Circuit High Voltage
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The hybrid drive motor generator battery contains 3 high voltage contactors also referred to as relays that allow the high voltage (HV) DC batteries to be connected to the vehicle. The three HV relays are a positive HV relay, negative HV relay and pre-charge relay. These relays/contactors close and open in a certain sequence and are controlled by the battery energy control module (BECM). The control circuit for the relays use a common ground and the BECM supplies voltage to turn them on and off individually. The BECM monitors the control circuit voltage to these relays. The BECM compares the HV relay control circuit voltage to the 12 volt accessory input circuit.
Conditions for Running the DTC
* Accessory voltage is 9-18 volts.
* Contactor commanded to OFF.
Conditions for Setting the DTC
The BECM measures more than 2 volts on the High Voltage contactor control circuit is more than 2 volts when commanded OFF.
Action Taken When the DTC Sets
* The malfunction indicator lamp (MIL) is illuminated.
* DTC P0AE7 is a Type B DTC.
Conditions for Clearing the DTC
DTC P0AE7 is a Type B DTC.
Special Tools
* EL-48569 Terminal Covers
* EL-48900 HEV Safety Kit
Circuit/System Verification
1. Ignition ON, engine OFF, with a scan tool, command the high voltage (HV) current limit relay ON and OFF several times. You should here the HV current limit relay click with each command.
2. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records data.
Circuit/System Testing
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.
Caution: High Voltage (HV) cables are not repairable. After disconnecting HV cables, protect and insulate ring terminal ends immediately with the EL-48569 terminal covers and UL(R) listed or equivalent insulation tape rated at a minimum of 600 volts. Damage caused to unprotected terminal ends will result in cable replacement.
Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling.
1. Remove the drive motor generator battery cover.
2. Connect the 12 volt battery.
3. Disconnect X8 at the HV current limit relay. Connect at test lamp between X8 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 test normal, replace the BECM.
4. With a scan tool, command the HV current limit relay ON. The test lamp should turn ON.
^ If the test lamp fails to illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BECM.
5. Disconnect X9 at the HV current limit relay. Connect a test lamp between X8 terminal 1 and X9 terminal 1.
6. With a scan tool, command the HV current limit relay ON. The test lamp should turn ON. If the test lamp fails to illuminate, test the ground circuit for an open/high resistance.
7. Connect the X8 and X9 to the HV current limit relay
8. Connect a DMM, across the high voltage contact side of HV current limit relay. With a scan tool, command the HV current limit relay ON. You should measure less than 0.5 ohms of resistance across the high voltage contact side.
^ If the resistance is greater than the specified value, replace the HV current limit relay.
Component Testing
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.
Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling.
1. Remove the drive motor generator battery cover.
2. Disconnect X8 and X9 at the HV current limit relay.
3. With a DMM measure between 60-70 ohms at 20°C (68°F) across X8 terminal 1 and X9 terminal 1 on the component harness side.
^ If the value is not within the specified range, replace the HV current limit relay.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair. Verification Tests
* Drive Motor Power Inverter Current Limit Relay Replacement
* Drive Motor Generator Battery Control Module and Bracket Replacement