Inspection Procedure
HINT:
If there is an open or short the engine coolant temperature sensor circuit, the ECM outputs DTCs (See DIAGNOSTIC TROUBLE CODE CHART ). Perform troubleshooting with the "SFI SYSTEM".
- READ VALUE OF INTELLIGENT TESTER (ENGINE COOLANT TEMPERATURE SIGNAL)
- Operate the intelligent tester according to the steps on the display and select "DATA LIST".
ENGINE
DATA LIST - ENGINETester Display Measurement Item/Range Normal Condition Diagnostic Note COOLANT TEMP Coolant temperature/Min.: -40°C (-40°F), Max.: 140°C (284°F) After warming up: 80 to 95°C (176 to 203°F) If the value is "-40°C (-40°F)" or "140°C (284°F)", sensor circuit is open or shorted OK:
Coolant temperature display on the tester is between 80°C (176°F) and 95°C (203°F) after warming up.
NG: GO TO ENGINE CONTROL SYSTEM
OK: Go to next step
- Operate the intelligent tester according to the steps on the display and select "DATA LIST".
- CHECK COMBINATION METER ASSEMBLY
- Disconnect the C6 meter connector.
- Using an oscilloscope, check the signal waveform of the meter.WAVEFORM REFERENCE
Tester Connection Tool Setting Vehicle Condition C6-21 - Body ground 5V/DIV., 10 ms./DIV. Ignition switch ON Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
OK:
Refer to Fig 1 .
NG: Go to step 3
OK: REPLACE COMBINATION METER ASSEMBLY
- CHECK WIRE HARNESS (COMBINATION METER ASSEMBLY - ECM)
- Disconnect the C6 meter connector.
- Disconnect the E5 ECM connector.
- Measure the resistance of the wire harness side connectors.
Standard resistance
RESISTANCE SPECIFICATIONTester Connection Specified Condition C6-21 - E5-14 (THWO) Below 1 Ω C6-21 - Body ground 10 kΩ or higher
NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: GO TO ENGINE CONTROL SYSTEM