DTC P26AC-11: Engine Coolant Bypass Valve "B" Circuit Short to Ground; DTC P26AC-15: Engine Coolant Bypass Valve "B" Circuit Short to Battery or Open [03/2022 - 03/2023]: Procedure
WARNING: This page is about a different car, the 2025 Lexus NX 250, 2024 Lexus NX 250, 2023 Lexus NX 250, and 2022 Lexus NX 250. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK TERMINAL VOLTAGE (POWER SOURCE OF FLOW SHUTTING VALVE (FOR ATF CONTROL))
- Disconnect the flow shutting valve (for ATF control) (No. 1 water by-pass hose) 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 B34-2 - Body ground Ignition switch ON 11 to 14 V Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI-MAIN NO. 1 RELAY - FLOW SHUTTING VALVE (FOR ATF CONTROL))
Result:
OK
See step 2
- INSPECT FLOW SHUTTING VALVE (FOR ATF CONTROL) (NO. 1 WATER BY-PASS HOSE)
Refer to INSPECTION [11/2021 - ]
Result
Proceed to OK NG Result:
NG
REPLACE FLOW SHUTTING VALVE (FOR ATF CONTROL) (NO. 1 WATER BY-PASS HOSE). Refer to REMOVAL [11/2021 - ]
Result:
OK
See step 3
- CHECK HARNESS AND CONNECTOR (FLOW SHUTTING VALVE (FOR ATF CONTROL) - ECM)
- Disconnect the flow shutting valve (for ATF control) (No. 1 water by-pass hose) connector.
- Disconnect the ECM connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition B34-1 - B50-41 (WSV2) Always Below 1 Ω B34-1 or B50-41 (WSV2) - Body ground and other terminals Always 10 kΩ or higher Result
Proceed to OK NG
Result:
OK
REPLACE ECM. Refer to REMOVAL [11/2021 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR