DTC P0125-00: Insufficient Coolant Temperature for Closed Loop Fuel Control [10/2022 - 08/2023]: Procedure
WARNING: This page is about a different car, the 2025 Lexus RX 350, 2024 Lexus RX 350, and 2023 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK ANY OTHER DTCS OUTPUT (IN ADDITION DTC P0125-00)
- Read the DTCs.
Powertrain > Engine > Trouble Codes
Result
Result Proceed to P0125-00 and other DTCs are output A P0125-00 is output B HINT:
If any DTCs other than P0125-00 are output, troubleshoot those DTCs first.
Result:
A
GO TO DTC CHART. Refer to DIAGNOSTIC TROUBLE CODE CHART [10/2022 - 08/2023]
Result:
B
See step 2
- Read the DTCs.
- INSPECT ENGINE COOLANT TEMPERATURE SENSOR (FOR OUTLET SIDE)
Refer to PROCEDURE - Step 1
Result
Proceed to OK NG Result:
NG
REPLACE ENGINE COOLANT TEMPERATURE SENSOR (FOR OUTLET SIDE). Refer to PROCEDURE - Step 2
Result:
OK
See step 3
- INSPECT ENGINE COOLANT TEMPERATURE SENSOR (FOR CYLINDER HEAD SIDE)
Refer to PROCEDURE - Step 3
Result
Proceed to OK NG Result:
NG
REPLACE ENGINE COOLANT TEMPERATURE SENSOR (FOR CYLINDER HEAD SIDE). Refer to PROCEDURE - Step 9
Result:
OK
See step 4
- CHECK ENGINE COOLING SYSTEM
- Check for defects in the engine cooling system that might cause the system to be too cold, such as abnormal cooling fan operation or any modifications.
Result
Proceed to OK NG
Result:
OK
REPLACE WATER CONTROL VALVE. Refer to REMOVAL [10/2022 - ]
Result:
NG
REPAIR OR REPLACE ENGINE COOLING SYSTEM
- Check for defects in the engine cooling system that might cause the system to be too cold, such as abnormal cooling fan operation or any modifications.