Inspection Procedure

WARNING: This page is about a different car, the 2007 Toyota Tacoma. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

If any of DTCs P0115, P0117, P0118 or P0125 are set simultaneously with DTC P0116, the ECT sensor may have an open or a short circuit. Troubleshoot those DTCs first.
Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was LEAN or RICH, and other data from the time the malfunction occurred.

CHECK ANY OTHER DTC OUTPUT (IN ADDITION TO DTC P0116)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the tester ON.
Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

Read DTCs.

Result

RESULT REFERENCE CHART

Display (DTC output)	Proceed to
P0116	A
P0116 and other DTCs	B

HINT:

If any DTCs other than P0116 are output, troubleshoot those DTCs first.

B: Go TO RELEVANT DTC CHART

A: Go to Next Step

INSPECT THERMOSTAT
1. Remove the thermostat (see REMOVAL ).
2. Check the valve opening temperature of the thermostat (see INSPECTION ).
  Standard opening temperature:
  
  80 to 84°C (176 to 183°F)
  
  HINT:
  
  In addition to the above check, confirm that the valve is completely closed when the temperature is below the standard.
3. Reinstall the thermostat (see INSTALLATION ).
NG: REPLACE THERMOSTAT

OK : REPLACE ENGINE COOLANT TEMPERATURE SENSOR