Troubleshooting

DTC P0116 - Engine Coolant Temperature Circuit Range / Performance Problem

CIRCUIT DESCRIPTION
A thermistor built into the engine coolant temperature sensor changes the resistance value according to the engine coolant temperature. The structure of the sensor and connection to the ECM is the same as in the intake air temperature circuit malfunction shown. If the ECM detects the DTC P0115, it operates the fail safe function in which the engine coolant temperature is assumed to be 80° C (176° F).





DETECTING CONDITIONS

Step 1:

Step 2:

INSPECTION PROCEDURE

HINT:
- If DTC "P0115" (Engine Coolant Temperature Circuit Malfunction) and "P0116" (Engine Coolant Temperature Circuit Range/Performance Problem) are output Simultaneously, engine coolant temp. sensor circuit may be open. Perform troubleshooting of DTC P0115 first.
- Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air-fuel ratio lean or rich etc. at the time of the malfunction.