Inspection Procedure

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.

Check engine coolant temperature sensor using hand-held tester.
PREPARATION: Connect the hand-held tester to the DLC3.

Check: the engine coolant temperature sensor using DATA LIST.
1. If OK , check or replace A/C amplifier.
2. NG: Go to step 2 .
Check engine coolant temperature sensor.
PREPARATION: Remove engine coolant temperature sensor.

Check: Measure resistance between terminals.

If OK , resistance is within acceptable zone on chart, see Fig 1.

Fig 1: Testing Engine Coolant Temperature Sensor
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: Engine Coolant Temperature Sensor Specifications
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Replace engine coolant temperature sensor.
2. OK: Go to step 3 .
Check for open and short in harness and connector between ECM and engine coolant temperature sensor . See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION .
1. NG: Repair or replace harness or connector.
2. If OK , check multiplex communication system. See HOW TO PROCEED WITH TROUBLESHOOTING MULTIPLEX COMMUNICATION SYSTEM .