P1A0C

DTC P1A0C or P1A0D

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 P1A0C
- Battery Energy Control Module System Voltage Low

DTC P1A0D
- Battery Energy Control Module System Voltage High

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 communication circuit. The drive motor generator control module is the host controller for diagnostic trouble code (DTC) information.

The drive motor generator battery control module continuously monitors the system voltage circuit. Low or higher than normal ignition voltage may be inadequate for operation of the energy storage components. Improper operation may cause erratic hybrid drive motor generator battery operation that could include a no start condition. A system over voltage longer than 8 minutes will cause the HV contactors coils to get hot. The drive motor generator battery control module will open the contactors. This will open the high voltage contactors when vehicle speed is below a calibrated value will not close them for 30 minutes in order to allow the contactors to cool.

Conditions for Running the DTC

The vehicle power mode is RUN.

Conditions for Setting the DTC

P1A0C

The drive motor generator battery control module detects the ignition voltage is less than 9 volts for 3 seconds.

P1A0D

The drive motor generator battery control module detects the ignition voltage is greater than 16 volts for 3 seconds.

Action Taken When the DTC Sets

P1A0C
* DTC P1A0C is a type C DTC.
* The drive motor generator battery control module commands the drive motor generator battery coolant fan to High.
* The drive motor generator battery control module will send a message to the drive motor generator control module to open the contactors.

P1A0D
* DTCs P1A0D is a Type C DTC.
* The drive motor generator battery control module commands the drive motor generator battery coolant fan to High.
* The drive motor generator battery control module will send a message to the drive motor generator control module to open the contactors.
* After 8 minutes of ignition voltage over 16 volts, the HV contactors will become hot and the drive motor generator battery control module will open the contactors.

Conditions for Clearing the DTC

* DTCs P1A0C and P1A0D are Type C DTCs.
* The control module ignition voltage is between 9-16 V.

Diagnostic Aids

Observe the driver information center messaging that would indicate the charging system requires service.

Inspect for the following conditions:

* Loose or poor connections at the drive motor generator battery control module X1 harness connector.
* Verify that the 12 V battery and charging system is within normal operating range and if a battery charger was connected to the vehicle.
* Loose or damaged battery terminals.
* Loose or corroded connections at the accessory dc power control module (APM).

Reference Information
Schematic Reference

Hybrid Energy Storage Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

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. Ignition ON, engine running, with a scan tool, monitor the control module voltage signal parameter in the data display list. The control module voltage should be between 12.5-15.5 V.

• If not within the specified range, refer to DC Power Conversion Test (Hybrid Controls - HP5).

2. Operate the vehicle within the Conditions for Running the DTCs. You may also operate the vehicle within the conditions that you observed from the Freeze Fame/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 DTCs P0A8D, P0A8E or P0A1F is not set.

• If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).

2. Ignition OFF, test for greater than 12.5 V at room temperature at the 12 V battery terminals.

• If not within the specified range, refer to Battery Inspection/Test (Battery Inspection/Test).

3. Start the engine and turn all accessories off.
4. Monitor the scan tool APM 12 V current parameter. Load test the 12 V battery at 175 A. The voltage parameter should display between 12.5-15.5 V.

• If not within specified value, replace the APM.

5. Monitor the scan tool Control Module Voltage Signal parameter. The voltage parameter should display between 12.5-15.5 V.

• If less than the specified range, test the ignition circuit terminal 19 X1 for an open/high resistance. If the circuits tests normal, replace the drive motor generator battery control module.
• If greater than the specified range, replace the drive motor generator battery control module.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the repair.

Control Module References (Programming and Relearning) for drive motor generator battery control module replacement, setup, and programming