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Home >> Chevrolet >> 2012 >> Volt L4-1.4L Elect >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0CE9

P0CE9




Hybrid/EV Electronics Coolant Pump Malfunction - DTC P0CE9 or P0CED

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 Descriptors
DTC P0CE9
- Hybrid/EV Electronics Coolant Pump Control Circuit

DTC P0CED
- Hybrid/EV Electronics Coolant Pump Enable Circuit

Circuit/System Description

The hybrid/EV electronics coolant pump circulates coolant through the drive motor battery coolant radiator, hybrid/EV powertrain control module 1, and the battery charger to control the temperature of the hybrid/EV powertrain control module 1 and the battery charger. An enable signal from the hybrid/EV powertrain control module 2 to the hybrid/EV electronics coolant pump provides overall control of the pump. When this circuit is high, the pump can operate. The pump is controlled with a pulse-width modulated signal from the hybrid/EV powertrain control module 2 to the hybrid/EV electronics coolant pump. The higher the duty cycle the higher the pump speed. The hybrid/EV electronics coolant pump provides a hard-wired pulse-width modulated feedback signal to the hybrid/EV powertrain control module 2. During normal operation, this feedback signal provides pump speed information. The hybrid/EV electronics coolant pump has some self-diagnostic capability. If it determines there is an internal fault it provides this information on this same feedback circuit instead of pump speed information.

Conditions for Running the DTC

P0CE9
* The 12 V battery voltage is greater than or equal to 9 V.
* The coolant pump enabled is commanded.

P0CED
* The 12 V battery voltage is greater than or equal to 9 V.
* The hybrid/EV powertrain control module 2 is awake and communicating.

Conditions for Setting the DTC

P0CE9

The hybrid/EV powertrain control module 2 has detected an open, short to voltage or short to ground on the coolant pump control circuit.

P0CED

The hybrid/EV powertrain control module 2 has detected an open, short to voltage or short to ground on the coolant pump enable circuit.

Action Taken When the DTC Sets

DTCs P0CE9 and P0CED are a type B DTCs.

Conditions for Clearing the DTC

DTCs P0CE9 and P0CED are a type B DTCs.

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

Circuit/System Verification

Vehicle in Service Mode, propulsion system active, with a scan tool, verify that the Hybrid Electronics Coolant Pump Command is between 20%-90% and Hybrid Electronics Coolant Pump Feedback is 50% +/-5%.

Circuit/System Testing

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. Verify that DTC P0C43, P0C44, P0C45, P0C47, or P1EC6 is not set.

• If DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

2. Vehicle OFF, disconnect the harness connector at the G35 hybrid/EV electronics coolant pump.
3. Vehicle OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 ohm between the ground circuit terminal 4 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

4. Connect a test lamp between the B+ circuit terminal 5 and the ground circuit terminal 4.
5. Vehicle in Service Mode, verify that a test lamp illuminates between the B+ circuit terminal 5 and ground circuit terminal 4.

• 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, test or replace the G35 hybrid/EV electronics coolant pump.

6. Connect a test lamp between the enable circuit terminal 1 and the ground circuit terminal 4.
7. Command the Hybrid Battery Pack Coolant Pump Command OFF (10%) and ON (90%) with a scan tool. The test lamp should turn OFF and ON when changing between the commanded states.

• If the test lamp is always illuminated at 10%, test the pump enable circuit for a short to voltage. If the circuit tests normal, replace the K114B hybrid/EV powertrain control module 2.
• If the test lamp does not illuminate at 90%, test the pump enable circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K114B hybrid/EV powertrain control module 2.

8. Connect a test lamp between the control circuit terminal 3 and the B+ circuit terminal 5.
9. Command the Hybrid Battery Pack Coolant Pump Command ON between 20% and 90% with a scan tool. Verify that a test lamp changes illumination between bright (20%) and dim (90%) between the control circuit terminal 3 and the B+ circuit terminal 5.

• If the test lamp is always dim or does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K114B hybrid/EV powertrain control module 2.
• If the test lamp is always bright, test the control circuit for a short to ground. If the circuit tests normal, replace the K114B hybrid/EV powertrain control module 2.

10. Verify the scan tool Hybrid/EV Electronics Coolant Pump Feedback parameter is less than 10%.

• If greater than the specified range, test the feedback circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K114B hybrid/EV powertrain control module 2.

11. Install a 3 A fused jumper wire between the feedback circuit terminal 2 and the ground circuit terminal 4. Verify the scan tool, Hybrid/EV Electronics Coolant Pump Feedback parameter is greater than 90%.

• If less that the specified range, test the feedback circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K114B hybrid/EV powertrain control module 2.

12. If all circuits test normal, replace the G35 hybrid/EV electronics coolant pump.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Generator Control Module Coolant Pump Replacement Generator Control Module Coolant Pump Replacement
* Control Module References Programming and Relearning for hybrid/EV powertrain control module 2 replacement, programming and setup

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