DTC P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) [08/2014 - 10/2015]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
5. Read the DTCs.

   Powertrain > Engine and ECT > Trouble Codes 

   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:  DIAGNOSTIC TROUBLE CODE CHART [08/2014 - 10/2015] 

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 INSPECTION [12/2012 - ]

Result: 

NG 

REPLACE THERMOSTAT:  REMOVAL [12/2012 - ] 

Result: 

OK 

See step  4

1. Inspect the engine coolant temperature sensor.

   Refer to INSPECTION [12/2012 - ]

Result: 

OK 

REPLACE ECM:  REMOVAL [12/2012 - ] 

Result: 

NG 

REPLACE ENGINE COOLANT TEMPERATURE SENSOR:  PROCEDURE - Step 1