DTC P0128: Thermostat [12/2015 - 08/2016]: Procedure
WARNING: This page is about a different car, the 2016 Toyota Sienna. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0128)
- Connect the Techstream to the DLC3.
- Turn the ignition switch to ON.
- Turn the Techstream on.
- Enter the following menus: Powertrain / Engine / Trouble Codes.
- Read DTCs.RESULT
Result Proceed to DTC P0128 is output A DTC P0128 and other DTCs are output B HINT:
If any DTCs other than P0128 are output, troubleshoot those DTCs first.
Result:
B
GO TO DTC CHART
(Refer to DIAGNOSTIC TROUBLE CODE CHART [12/2015 - 08/2016] )
Result:
A
See step 2
- CHECK COOLING SYSTEM
- Check for defects in the cooling system that might cause the system to be too cold, such as abnormal radiator fan operation or any modifications.
Result:
NG
REPAIR OR REPLACE COOLING SYSTEM
(Refer to ON-VEHICLE INSPECTION [12/2015 - 08/2016] )
Result:
OK
See step 3
- INSPECT THERMOSTAT
- Check the valve opening temperature of the thermostat (Refer to INSPECTION [12/2015 - 08/2016] ).
Result:
NG
REPLACE THERMOSTAT
(Refer to REMOVAL [12/2015 - 08/2016] )
Result:
OK
See step 4
- INSPECT ENGINE COOLANT TEMPERATURE SENSOR
- Inspect the engine coolant temperature sensor (Refer to REMOVAL [12/2015 - 08/2016]
).
HINT:
Perform "Inspection After Repair" after replacing the engine coolant temperature sensor (Refer to INITIALIZATION [12/2015 - 08/2016] ).
Result:
OK
REPLACE ECM
(Refer to REMOVAL [12/2015 - 08/2016] )
Result:
NG
REPLACE ENGINE COOLANT TEMPERATURE SENSOR
(Refer to REMOVAL [12/2015 - 08/2016] )
- Inspect the engine coolant temperature sensor (Refer to REMOVAL [12/2015 - 08/2016]
).