Inspection Procedure

HINT:

• If DTCs P0115, P0116, P0117, P0118 and P0125 are output simultaneously, engine coolant temperature sensor circuit may be open or short. Perform the troubleshooting of DTC P0115, P0117 or P0118 first.
• Read freeze frame data using the hand-held 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.

1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0125) 
   1. Read the DTC using the hand-held tester.

   Result: 

   Fig 1: Result Chart

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT:

   If any other codes besides "P0125" is output, perform the troubleshooting for those codes first.

   1. B: GO TO RELEVANT DTC CHART (See  DIAGNOSTIC TROUBLE CODE CHART   ) 
   2. A: Go to next step. 
2. INSPECT THERMOSTAT (See ) 
   1. NG: REPLACE THERMOSTAT (See ) 
   2. OK: Go to next step. 
3. CHECK COOLING SYSTEM 
   1. Check that there is a defect in the cooling system which causes overcool, such as abnormal radiator fan operation, modified cooling system and so on.
   1. NG: REPAIR OR REPLACE COOLING SYSTEM 
   2. OK: Go to next step. 

      REPLACE ECT SENSOR