Engine Coolant Temperature Gauge Malfunction: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Powertrain / Engine and ECT / Data List.
5. Check the values by referring to the table below.

   Engine and ECT

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Coolant Temp	Coolant temperature/Min.: -40°C (-40°F), Max.: 140°C (284°F)	80 to 100°C (176 to 212°F): After warming up	If -40°C (-40°F): sensor circuit open If 140°C (284°F) or more: sensor circuit shorted

   OK

   Coolant temperature display on the Techstream is between 80°C (176°F) and 100°C (212°F) after warming up.

NG → GO TO ENGINE CONTROL SYSTEM 

OK: Go to next step 

Fig 1: Identifying C6 Combination Meter Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the C6 meter connector.
2. Using an oscilloscope, check the signal waveform of the meter.

   Tester Connection	Tool Setting	Vehicle Condition
   C6-21 - Body ground	5 V/DIV., 10 ms./DIV.	Ignition switch ON

   OK

   Refer to the illustration above.

NG → See step   3 

OK → REPLACE COMBINATION METER ASSEMBLY 

Fig 2: Identifying Combination Meter And ECM Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the C6 meter connector.
2. Disconnect the E5 ECM connector.
3. Measure the resistance of the wire harness side connectors.

   Standard resistance

   Tester 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