P1AE7
DTC P1AE7
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC P1AE7
- Battery Energy Control Module Hybrid Battery Voltage System Isolation Fault.
Typical Scan Tool Data
Circuit/System Description
The drive motor generator battery control module will diagnose its own systems and determine when a fault condition is present. Diagnostics and system status is communicated from the drive motor generator battery control module to the drive motor generator control module through the serial data circuit. The drive motor generator control module is the host controller for diagnostic trouble code (DTC) information.
The vehicle is equipped with a high voltage (HV) isolation monitor feature. The purpose of the HV isolation circuit is to test the resistance between the HV positive and negative direct current (DC) bus and chassis ground. The drive motor generator battery control module only runs this test when the ignition transitions from ON to OFF the HV contactors have opened and the drive motor generator battery control module is still awake. The drive motor generator battery control module has an internal Isolation sensor that measures the resistance between the HV DC positive and negative bus and chassis ground. The drive motor generator battery control module runs an internal self check of this sensor circuit. If the internal self check fails DTC P1AE7 will set. This DTC indicates that the fault is in the drive motor generator battery. Because this diagnostic runs after system power down, the diagnostic status does not get reported until the next ignition cycle.
Conditions for Running the DTC
* Accessory voltage is 9-18 volts.
* The ignition switch transitions from ON to OFF.
* HV contactors transition to open.
Conditions for Setting the DTC
* The drive motor generator battery control module has detected a loss of isolation between the high voltage positive or negative bus to chassis ground that is less than 200 k ohms.
* This diagnostic may take up to 20 seconds to run after the conditions for running have been met. This DTC will not report the status until the next ignition cycle.
Action Taken When the DTC Sets
DTC P1AE7 is Type C DTC.
Conditions for Clearing the DTC
DTC P1AE7 is Type C DTC.
Diagnostic Aids
A single high voltage contactor stuck closed can set this DTC. If a high voltage contactor is closed when this test runs, the drive motor generator battery control module circuitry in the power inverter module will cause a loss of isolation to be detected.
Reference Information
Schematic Reference
Hybrid Energy Storage Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
* Hybrid Modes of Operation Description (Hybrid Modes of Operation Description)
* Drive Motor Generator Battery Description (Drive Motor Generator Battery Identification Information)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Special Tools
EL-48900 HEV Safety Kit
Circuit/System Verification
1. Observe the scan tool parameter 300 V Isolation Test Status parameter. The scan tool should indicate Passed.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from 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.
1. Verify that DTC P1A1F is not set.
• If the DTC is set, Refer to DTC P1A1F or P1A4E (P1A1F).
2. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling.
3. Connect the 12 V battery.
4. Ignition ON, engine OFF, test for greater than 5 ohm between the HV positive contactor terminals 2 and 5 and between the HV negative contactor terminals 3 and 6. Refer to Saturn Vue-Hybrid Battery Connections for terminal identification.
• If less than the specified range, replace the drive motor battery disconnect control module.
5. Disconnect the X4 harness connector at the drive motor generator battery disconnect control module.
6. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 7 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the drive motor generator battery control module.
7. Ignition OFF, connect a test lamp between the B+ circuit terminal 7 and the control circuit terminal 8.
8. Ignition ON, with a scan tool command the HV positive contactor open and closed several times. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit tests normal, replace the drive motor generator battery control module.
• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the drive motor generator battery control module.
9. Ignition OFF, connect a test lamp between the B+ circuit terminal 7 and the control circuit terminal 10.
10. Ignition ON, with a scan tool command the HV negative contactor open and closed several times. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit tests normal, replace the drive motor generator battery control module.
• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the drive motor generator battery control module.
11. If all circuits test normal, replace the drive motor battery assembly.
Repair Instructions
Note: If you are preparing the drive motor generator battery for shipment, Install the terminal extension cover assembly and retaining bolts. Using UL(R) 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 (Verification Tests) after completing the repair.
* Drive Motor Generator Battery Replacement (Drive Motor Generator Battery Control Module and Bracket Replacement)
* Control Module References (Programming and Relearning) for drive motor generator battery control module replacement, setup and programming