P1EC6
Hybrid/EV Battery Pack Coolant Heater Malfunction - DTC P1EC6
Diagnostic Instructions
* 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 Descriptor
DTC P1EC6
- Hybrid/EV Battery Pack Heater Performance
Circuit/System Description
The hybrid/EV battery contains 5 high voltage contactors and 2 transistors. The high voltage contactors allow the high voltage DC batteries to be connected to the vehicle or safely contain the high voltage DC within the hybrid/EV battery assembly. The 5 high voltage contactors are a main positive high voltage contactor, main negative high voltage contactor, charge positive high voltage contactor, charge negative high voltage contactor, and multi-function high voltage contactor. The 2 transistors are the precharge transistor and heater transistor. These contactors/transistors close and open in sequence and are controlled by the hybrid/EV powertrain control module 2. The hybrid/EV powertrain control module 2 supplies voltage to the control circuit for the high voltage contactors/transistors. Ground is provided through the case ground.
The hybrid/EV battery pack coolant heater is mounted to the coolant inlet on the back side of the hybrid/EV battery contactor assembly. They hybrid/EV battery pack coolant heater uses a 360 V power source.
After the vehicle is turned ON, the hybrid/EV battery pack coolant heater is commanded ON. The hybrid/EV powertrain control module 2 monitors the temperature change at the hybrid/EV battery pack coolant temperature sensor 1 to determine if the hybrid/EV battery pack coolant heater is functioning properly.
Conditions for Running the DTC
* The 12 V battery voltage is greater than or equal to 9 V.
* The vehicle is not connected to an active AC source.
* The hybrid/EV battery pack coolant temperature sensor 1 is less than 45°C (113°F).
* The difference between the hybrid/EV battery pack coolant temperature sensor 1 and the hybrid/EV battery average cell temperature is less the 25°C (77°F)
* Runs once per ignition cycle when propulsion system goes active.
* None of the following DTCs are set; P1EC3, P1EC4, P1EC5, P0C44, P0C45, P1F18, P0C47, or U0111.
Conditions for Setting the DTC
The hybrid/EV powertrain control module 2 did not see the battery pack coolant temperature sensor 1 rise fast enough during the test period of one minute. The required increase in temperature is approximately 1°C (1.8°F) change for every 2 seconds.
Action Taken When the DTC Sets
* DTC P1EC6 is a type B DTC.
* The hybrid/EV battery pack coolant heater will be disabled.
Conditions for Clearing the DTC
DTC P1EC6 is a type B DTC.
Diagnostic Aids
* P1EC6 will prevent battery heating and the vehicle will be unable to start in cold weather with battery temperatures below -25°C (-13°F).
* A malfunctioning pack heater may have discoloration of the metal housing or the metal housing may be deformed.
Reference Information
Schematic Reference
Hybrid Cooling Schematics Hybrid Cooling Schematics
Connector End View Reference
Component Connector End Views Hybrid/EV Battery Pack X1
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 Programming and Relearning for scan tool information
Special Tools
* EL-48900 - HEV Safety Kit
* EL-50772 - Insulation Multimeter
For equivalent regional tools, refer to Special Tools Tools and Equipment.
Circuit/System Verification
1. Vehicle in Service Mode, with the hybrid/EV battery pack coolant pump is disabled and not running, verify the scan tool parameters listed below:
* Hybrid/EV Battery Pack Coolant Pump Command is less than 10%.
* Hybrid/EV Battery Pack Coolant Pump Feedback is 0%.
* Hybrid/EV Battery Pack Coolant Pump Speed is 25 RPM.
• With the hybrid/EV battery pack coolant pump is disabled and not running and the scan tool parameters listed are not the specified values, refer to Hybrid/EV Battery Pack Coolant Pump Malfunction - DTC P0C47, P0C4A, or P1F18 P0C47.
2. Vehicle OFF, connect the charge cord set. With the vehicle in Charge Mode, the hybrid/EV battery pack coolant pump enabled and not running, verify the scan tool parameters listed below:
* Hybrid/EV Battery Pack Coolant Pump Command is 10%.
* Hybrid/EV Battery Pack Coolant Pump Feedback to be 50% +/-5%.
* Hybrid/EV Battery Pack Coolant Pump Speed is 50 RPM.
• With the vehicle in Charge Mode, the hybrid/EV battery pack coolant pump enabled and not running and the scan tool parameters listed are not the specified values, refer to Hybrid/EV Battery Pack Coolant Pump Malfunction - DTC P0C47, P0C4A, or P1F18 P0C47.
Note: The vehicle must be in Charge Mode and the pump is enabled and not running before proceeding to the next step.
3. Vehicle in Service Mode, command the Hybrid/EV Battery Pack Coolant Pump Heater to 90 kW with a scan tool. Observe the Hybrid/EV Battery Pack Coolant Pump Temperature Sensor 1 parameter. The temperature reading should rise after a 15-second delay, +/- 10 seconds, to above 54°C +/-5°C (129.2°F +/-10°).
• With the vehicle in Charge Mode, Vehicle in Service Mode, Hybrid/EV Battery Pack Coolant Pump Heater commanded to 90 kW and the Hybrid/EV Battery Pack Coolant Pump Temperature Sensor 1 temperature is less than the specified value, refer to Circuit/System Testing.
Note: The hybrid/EV powertrain control module 2 will turn on the hybrid/EV battery pack coolant pump once a calibrated temperature is reached.
Note: Do not run the test for more than 15 seconds after the Hybrid/EV Battery Pack Coolant Pump Temperature Sensor 1 reaches 54°C (129.2°F).
4. With the hybrid/EV battery pack coolant pump enabled and running with the Hybrid/EV Battery Pack Coolant Pump Temperature Sensor 1 parameter above 54°C +/-5°C (129.2°F +/-10°), verify the scan tool parameters listed below:
* Hybrid/EV Battery Pack Coolant Pump Command to be greater than 10%.
* Hybrid/EV Battery Pack Coolant Pump Feedback to be 50% +/-5%.
* Hybrid/EV Battery Pack Coolant Pump Speed is greater than 50 RPM.
• With the vehicle in Charge Mode, Vehicle in Service Mode, the hybrid/EV battery pack coolant pump enabled and running and the scan tool parameters listed are not the specified values, refer to Hybrid/EV Battery Pack Coolant Pump Malfunction - DTC P0C47, P0C4A, or P1F18 P0C47.
5. Verify that the Hybrid/EV Battery Pack Coolant Pump Temperature Sensor 1 parameter dropped to below 40°C (104°F) after a 15-second delay, +/- 10 seconds, with the hybrid/EV battery pack coolant pump running.
• The Hybrid/EV Battery Pack Coolant Pump Temperature Sensor 1 parameter did not drop to below 40°C (104°F) with the hybrid/EV battery pack coolant pump running. Refer to Hybrid/EV Battery Cooling Diagnostic Hybrid/EV Battery Cooling Diagnostic.
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 includes the following steps:
* 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 may result in serious injury or death.
Danger: The Volt Battery Pack will utilize an exchange program. Please consult the most recent revision of bulletin/PI #PIP4841, available in Service Information (SI), for a list of approved Volt Battery Pack service procedures. Components that may be removed and serviced without exchanging the complete battery pack are identified in the bulletin/PI. Please contact the GM Technical Assistance Center if you have any questions.
1. Vehicle in Service Mode, verify that DTC P0AA1, P0AD9, P0ADD, P0AE2, P0AE4, P0AFA, P0D0A, P0D11, P1EBC-P1EBF, P1EC0, P1EC3-P1EC5 P0C44, P0C45, P0C47 or P1F18, is not set.
• If DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
2. Vehicle OFF, disable the high voltage at the A4 hybrid/EV battery pack. Refer to High Voltage Disabling High Voltage Disabling.
3. Remove the Drive Motor Battery Cover. Refer to Drive Motor Battery Cover Replacement Drive Motor Battery Cover Replacement.
4. Disconnect the harness connector at the E54 hybrid/EV battery pack coolant heater.
5. Test for 61-75 ohms between terminal A and terminal B at the E54 hybrid/EV battery pack coolant heater.
• If not within the specified range, verify that the 20 A charger maxi-fuse is not blown. Replace the 20 A charger maxi-fuse if it is blown and the E54 hybrid/EV battery pack coolant heater.
Note: The following continuity tests must be performed using an EL-50772 Insulation Multimeter. Select the Isolation test setting, then select the 500 V range.
6. With the EL-50772, set on the Isolation test setting, test for 550M ohms between the E54 hybrid/EV battery pack coolant heater terminals listed below and battery tray ground:
* Terminal A
* Terminal B
• If less than the specified value, verify that the 20 A charger maxi-fuse is not blown. Replace the 20 A charger maxi-fuse if it is blown and the E54 hybrid/EV battery pack coolant heater.
7. If all the circuit tests normal, replace the A28 hybrid battery contactor assembly.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Battery Heater Replacement Battery Heater Replacement - E54 hybrid/EV battery pack coolant heater
* Battery Charger and 14 V Power Module Maxi 20 A Fuse Replacement Battery Charger and 14 V Power Module Maxi 20 A Fuse Replacement
* Drive Motor Battery Wire Junction Block Relay Replacement Drive Motor Battery Wire Junction Block Relay Replacement - A28 hybrid battery contactor assembly