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P26A3




DTC P2681, P26A3, P26A6, P26A7, or P26A9

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 P2681
- Engine Coolant Bypass Valve Control Circuit

DTC P26A3
- Engine Coolant Bypass Valve Performance

DTC P26A6
- Engine Coolant Bypass Valve Position Sensor Circuit Low Voltage

DTC P26A7
- Engine Coolant Bypass Valve Position Sensor Circuit High Voltage

DTC P26A9
- Engine Coolant Bypass Valve Position Sensor Stop Performance

Diagnostic Fault Information






Circuit/System Description

The passenger compartment heater coolant control valve regulates the engine coolant flow into the cabin heater loop depending on engine coolant temperature and ambient temperature conditions. The passenger compartment heater coolant control valve has two positions: ByPass or Link. In the ByPass position, the coolant in the engine loop and heater loop are separated and in the link position the coolant circulates through both loops. The valve movement is controlled by a PWM signal. A 50% duty cycle is a normal duty cycle. A 75% duty cycle represents a valve commanded to the link position. A 25% duty cycle represents a valve commanded to the ByPass position. The passenger compartment heater coolant control valve uses an internal position sensor that sends a signal to the hybrid powertrain control module 2 to determine the valve position.

When the engine coolant temperature heats up, a valve learn procedure takes place. The hybrid powertrain control module 2 commands the valve to the link position and records the voltage coming back from the position sensor. Then the hybrid powertrain control module 2 commands the valve back to the bypass position and records the voltage coming back from the position sensor. The voltage values in both the link and bypass positions must fall within calibrated ranges.

Conditions for Running the DTC

P2681, P26A6 and P26A7

12 V battery system voltage is greater than or equal to 10.25 V.

P26A3 and P26A9

* 12 V battery system voltage is greater than or equal to 10.25 V.

* The propulsion system is active.

* None of the following DTCs are set; P2681, P26A6, P26A7.

Conditions for Setting the DTC

P2681

The hybrid powertrain control module 2 has detected a short to voltage or an open on valve drive circuit.

P26A6

The hybrid powertrain control module 2 has detected a short to ground on feedback circuit. The feedback signal is less than 5% (0.25 V).

P26A7

The hybrid powertrain control module 2 has detected a short to voltage on feedback circuit. The feedback signal is greater than 95% (4.25 V).

P26A3

* The hybrid powertrain control module 2 has detected a stuck valve.

* The valve did not reach the commanded position within 15 seconds after 3 attempts to move the valve.

* The coolant temperature is above 50° C.
OR

* The hybrid powertrain control module 2 has detected a stuck valve.

* The valve did not reach the commanded position within 15 seconds

* The coolant temperature is above 65° C.

P26A9

* The feedback signal is between 70% - 95% (3.5 - 4.75 V) or between 5% - 30% (0.25-1.5 V)
OR

* The hybrid powertrain control module 2 has detected the valve feedback has drifted beyond acceptable range.
OR

* The hybrid powertrain control module 2 has detected the valve feedback to be erratic beyond acceptable range.

Action Taken When the DTC Sets

DTCs P2681, P26A3, P26A6, P26A7 and P26A9 are type B DTCs.

Conditions for Clearing the DTC

* DTCs P2681, P26A3, P26A6, P26A7 and P26A9 are type B DTCs.

* DTC P26A3 requires the ignition to cycle from ON to OFF.

Reference Information

Schematic Reference

HVAC Schematics Electrical Diagrams

Connector End View Reference

Component Connector End Views Hybrid/EV Battery Pack X1

Description and Operation

Automatic HVAC Description and Operation HVAC - Automatic

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

1. Vehicle in Service Mode.

2. Verify that DTC P0606, P0CE7, P2518 or P26A7 is not set.

• If any of the DTCs are set
Refer to DTC P151C or P2516-P2518 P151C

• If none of the DTCs are set

3. Refer to Circuit/System testing

Circuit/System Testing

1. Vehicle OFF and all vehicle systems OFF, disconnect the harness connector at the Q66 passenger compartment heater coolant control valve. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 5 ohms between the ground circuit terminal 6 and ground.

• If 5 ohms or greater

1. Vehicle OFF.

2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, repair the open/high resistance in the ground connection.

• If less than 5 ohms

3. Test for less than 5 ohms between the low reference circuit terminal 5 and ground.

• If 5 ohms or greater

1. Disconnect the harness connector at the K114B hybrid powertrain control module 2.

2. Test for less than 2 ohms in the low reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K114B hybrid powertrain control module 2.

• If less than 5 ohms

4. Vehicle in Service Mode.

5. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.

• If the test lamp does not illuminate and the circuit fuse is good

1. Vehicle OFF.

2. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.

• If the test lamp does not illuminate and the circuit fuse is open

1. Vehicle OFF.

2. Test for infinite resistance between the B+ circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the Q66 passenger compartment heater coolant control valve.

• If the test lamp illuminates

6. Test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground.

• If less than 4.8 V

1. Vehicle OFF, disconnect the X1 harness connector at the K114B hybrid powertrain control module 2.

2. Test for infinite resistance between the 5 V reference circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance

3. Test for less than 2 ohms in the 5 V reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K114B hybrid powertrain control module 2.

• If greater than 5.2 V

1. Vehicle OFF, disconnect the X1 harness connector at the K114B hybrid powertrain control module 2, vehicle in Service Mode.

2. Test for less than 1 V between the 5 V reference circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V, replace the K114B hybrid powertrain control module 2.

• If between 4.8-5.2 V

7. Verify the scan tool Hybrid Powertrain Control Module 2, Passenger Compartment Heater Coolant Control Solenoid Valve Feedback parameter is greater than 95%.

• If less than 95%

1. Vehicle OFF, disconnect the X1 harness connector at the K114B hybrid powertrain control module 2.

2. Test for infinite resistance between the signal circuit terminal 4 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the K114B hybrid powertrain control module 2.

• If greater than 95%

8. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 5.

9. Verify the scan tool Passenger Compartment Heater Coolant Control Solenoid Valve Feedback parameter is less than 10%.

• If 10% or greater

1. Vehicle OFF, disconnect the harness connector at the K114B hybrid powertrain control module 2, vehicle in Service Mode.

2. Test for less than 1 V between the signal circuit terminal 4 and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V

3. Vehicle OFF.

4. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K114B hybrid powertrain control module 2.

• If less than 10%

10. Verify a test lamp illuminates between the control circuit terminal 2 and the B+ circuit terminal 1

Note: It may take up to 5 seconds for illumination to occur.

• If the test lamp does not illuminate

1. Vehicle OFF, disconnect the harness connector at the K114B hybrid powertrain control module 2, vehicle in Service Mode.

2. Test for less than 1 V between the control circuit and ground

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V

3. Vehicle OFF

4. Test for less than 2 ohms on the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K114B hybrid powertrain control module 2.

• If the test lamp illuminates

11. Vehicle OFF, disconnect the harness connector at the K114B hybrid powertrain control module 2.

12. Test for infinite resistance between the control circuit terminal 2 and ground.

• If less than infinite resistance
Repair the short to ground on the circuit

• If infinite resistance

13. Replace the Q66 passenger compartment heater coolant control valve.

14. Verify the DTC does not set while operating the vehicle under the Conditions for Running the DTC.

• If the DTC sets
Replace the K114B hybrid powertrain control module 2.

• If the DTC does not set

15. All OK.

Repair Instructions

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

* Heater Water Shutoff Valve Replacement Service and Repair

* Control Module References Programming and Relearning for the hybrid powertrain control module 2 replacement, programming and setup

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