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 ignition 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).
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
For equivalent regional tools, refer to Special Tools Tools and Equipment.
Circuit/System Verification
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 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 (1-877-446-8227) if you have any questions.
1. Vehicle OFF, disable the high voltage at the A4 hybrid/EV battery pack. Refer to High Voltage Disabling High Voltage Disabling.
2. If the DTC is set, replace the A28 hybrid/EV battery contactor assembly.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
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