DTC P26CA-12: Engine Coolant Pump Circuit Short to Battery [11/2022 - ]: Procedure
WARNING: This page is about a different car, the 2025 Toyota Corolla Cross, 2024 Toyota Corolla Cross, and 2023 Toyota Corolla Cross. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK TERMINAL VOLTAGE (POWER SOURCE OF INVERTER WATER PUMP WITH MOTOR ASSEMBLY)
*a Front view of wire harness connector
(to Inverter Water Pump with Motor Assembly)- Disconnect the inverter water pump with motor assembly connector.
- Turn the ignition switch to ON.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition C131-3 (SWP) - Body ground Ignition switch ON Below 1 V Result
Proceed to OK NG
Result:
NG
See step 3
Result:
OK
See step 2
- INSPECT ECM (INTERNAL CIRCUIT)
*a Front view of wire harness connector
(to Inverter Water Pump with Motor Assembly)- Disconnect the inverter water pump with motor assembly connector.
- Turn the ignition switch to ON.
- Perform the Active Test using the GTS.
Powertrain > Engine > Active Test
Tester Display Activate the Electric Water Pump - Measure the resistance according to the value(s) in the table below.
Standard
Tester Connection Condition Specified Condition C131-3 (SWP) - Body ground During Active Test Resistance fluctuates* HINT:
- *: When the connector of the inverter water pump with motor assembly is disconnected, the ECM will enter fail-safe mode. In this case, duty control of the transistors in the ECM will be performed and resistance fluctuates.
- If the resistance fluctuates while the ECM is in fail-safe mode after the connector of the inverter water pump with motor assembly is disconnected, it can be determined that the transistor is operating.
- If the transistor does not operate, the ECM may be malfunctioning.
- If the resistance fluctuates after turning the ignition switch to ON, it can be determined that the ECM is in fail-safe mode.
Result
Proceed to OK NG
Result:
OK
REPLACE INVERTER WATER PUMP WITH MOTOR ASSEMBLY. Refer to REMOVAL [11/2022 - ]
Result:
NG
REPLACE ECM. Refer to REMOVAL [11/2022 - ]
- CHECK HARNESS AND CONNECTOR (INVERTER WATER PUMP WITH MOTOR ASSEMBLY - ECM)
- Disconnect the inverter water pump with motor assembly connector.
- Disconnect the ECM connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition C131-3 (SWP) or C139-50 (WPO) - Other terminals Always 10 kΩ or higher Result
Proceed to OK NG
Result:
OK
REPLACE ECM. Refer to REMOVAL [11/2022 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR