DTC P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) [10/2014 - ]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
5. Read the 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 [10/2014 - 10/2015] or DIAGNOSTIC TROUBLE CODE CHART [10/2015 - 10/2016] or DIAGNOSTIC TROUBLE CODE CHART [10/2016 - 06/2017] or DIAGNOSTIC TROUBLE CODE CHART [06/2017 - ] )

Result: 

A 

See step  2

1. Check for defects in the cooling system that might cause the system to be too cold, such as abnormal cooling fan operation or any modifications.

Result: 

NG 

REPAIR OR REPLACE COOLING SYSTEM 

Result: 

OK 

See step  3

1. Inspect the thermostat opening temperature (Refer to PROCEDURE - Step 1 ).

Result: 

NG 

REPLACE WATER INLET WITH THERMOSTAT SUB-ASSEMBLY 

(Refer to REMOVAL [10/2014 - ] )

Result: 

OK 

See step  4

1. Inspect the engine coolant temperature sensor (Refer to INSPECTION [10/2014 - ] ).

   HINT: 

   Perform "Inspection After Repair" after replacing the engine coolant temperature sensor (Refer to INITIALIZATION [10/2014 - ] ).

Result: 

OK 

REPLACE ECM 

(Refer to REMOVAL [10/2014 - ] )

Result: 

NG 

REPLACE ENGINE COOLANT TEMPERATURE SENSOR 

(Refer to REMOVAL [10/2014 - ] )