P0D64
DTC P0D64-P0D66
Diagnostic Instructions
Danger: This diagnostic has NOT been validated on-vehicle. Follow all safety protocol and utilize all appropriate personal protective equipment to ensure your safety. Failure to follow the procedures exactly as written may result in serious injury or death.
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P0D64
- Hybrid Battery Pack Cooling Fan Enable Circuit
DTC P0D65
- Hybrid Battery Pack Cooling Fan Enable Circuit Low Voltage
DTC P0D66
- Hybrid Battery Pack Cooling Fan Enable Circuit High Voltage
Circuit/System Description
The hybrid/EV battery pack cooling fan draws air through the hybrid/EV battery pack to control the temperature of the hybrid/EV battery pack. To operate, the cooling fan receives an enable signal from the starter/generator control module. The enable control is controlled by a discrete high side driver in the starter/generator control module. When the enable control circuit is high, the fan will be enabled. The fan speed is controlled by a fan control circuit in the starter/generator control module, by changing the duty cycle. Maximum fan speed is 3900 RPM. Hybrid/EV battery pack cooling fan Enable circuit open and short to voltage diagnostics run continuously until hybrid/EV battery pack cooling fan is enabled to run while short to ground runs after it is enabled to run. These diagnostics detect and report a failure of the fan Enable circuits.
Conditions for Running the DTC
P0D64 or P0D66
* Ignition is RUN or CRANK
* The hybrid/EV battery pack cooling fan is not enabled
P0D65
* Ignition is RUN or CRANK
* The hybrid/EV battery pack cooling fan is enabled
Conditions for Setting the DTC
P0D64
An open is detected on the hybrid/EV battery pack cooling fan enable control circuit
P0D65
A short to ground is detected on the hybrid/EV battery pack cooling fan enable control circuit
P0D66
A short to voltage is detected on the hybrid/EV battery pack cooling fan enable control circuit
Action Taken When the DTC Sets
DTCs P0D64, P0D65, and P0D66 are type B DTCs
Conditions for Clearing the DTC
DTCs P0D64, P0D65, and P0D66 are type B DTCs
Reference Information
Schematic Reference
Hybrid Cooling Schematics Hybrid Cooling Schematics
Connector End View Reference
Component Connector End Views Connector End Views By Name
Description and Operation
Hybrid Cooling System Description and Operation Hybrid Cooling System Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
Ignition ON, command the Hybrid Battery Fan Speed between 10%-90% with a scan tool. Verify that the hybrid battery pack cooling fan speed increases and decreases with the command.
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.
Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:
* Safety glasses with appropriate side shields when within 15 meters (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 with leather protectors at all times when working with the high voltage battery assembly, whether the system is energized or not.
Failure to follow the procedures exactly as written may result in serious injury or death.
Danger: The eAssist battery pack assembly will utilize an exchange program. Please consult the most recent revision of bulletin/PI #PIPXXYYZZ, available in Service Information (SI), for a list of approved eAssist battery pack assembly service procedures. Components that may be removed and serviced without exchanging the complete battery pack assembly are identified in the bulletin/PI. Please contact the GM Technical Assistance Center (1-877-446-8227) if you have any questions.
1. Ignition OFF, disconnect the harness connector at the G14 hybrid/EV battery pack cooling fan.
2. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 10 ohm between the ground circuit terminal 1 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 5 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 and the B+ circuit fuse is open, replace the G14 hybrid/EV battery pack cooling fan.
4. Connect a test lamp between the control circuit terminal 4 and ground.
5. Command the Hybrid Battery Fan Speed OFF (10%) and ON (90%) with a scan tool. Verify the test lamp turns OFF and ON when changing between the commanded states.
• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K59 starter/generator control module.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K59 starter/generator control module.
6. Connect a test lamp between the signal circuit terminal 3 and ground.
7. Command the Hybrid Battery Fan Speed between 10% and 90% with a scan tool. Verify that the test lamp illumination changes between bright (10%) and dim (90%).
• If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K59 starter/generator control module.
• If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K59 starter/generator control module.
• If the test lamp illuminates, but does not change in intensity, replace the K59 starter/generator control module.
8. Verify the scan tool Hybrid Battery Fan Speed parameter is less than 100 RPM.
• If greater than the specified range, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K59 starter/generator control module.
9. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the ground. Verify the scan tool, Hybrid Battery Fan Speed parameter is greater than 1000 RPM.
• If less that the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K59 starter/generator control module.
10. If all circuits test normal, replace the G14 hybrid/EV battery pack cooling fan.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Drive Motor Battery Cooling Blower Replacement Drive Motor Battery Cooling Blower Replacement
* Control Module References Control Module References for starter/generator control module replacement, programming, and setup