Transmission Control Systems
TROUBLE CODE 21 - ATF TEMPERATURE SENSORCONTENT OF DIAGNOSIS:
Input signal circuit of TCU to ATF temperature sensor is open or shorted.
TROUBLE SYMPTOM:
^ No shift up to 4th speed (after engine warm-up)
^ No lock-up occurs (after engine warm-up)
^ Excessive shift shock
1. MEASURE SIGNAL VOLTAGE INPUT OF TCU.
1) Turn ignition switch ON (with engine OFF) and measure signal voltage input of TCU.
2) Start and warm up the engine. Measure signal voltage input of TCU.
(Connector) terminal: Specified voltage
(B44) No.10 - (B46) No.20:
1.4 - 1.7 V [A/F temperature: 20°C (68°F)]
0.3 - 0.6 V [A/F temperature: 8O°C (176°F)]
SELECT MONITOR FUNCTION MODE
Mode: GB
Condition: Warm up the engine to increase ATF temperature.
Specified data: ATFT FO8 or F07
(Temperature shown on display increases)
2. CHECK HARNESS BETWEEN TCU AND ATF TEMPERATURE SENSOR.
1) Disconnect connector from TCU.
2) Disconnect connector from transmission.
3) Measure resistance between TCU connector and transmission connector, and between TCU connector and body.
(Connector) terminal: Specified voltage
(B44) No.10 - (B16) No.5: 1 Ohm
(B44) No.10 - Body: 1 M Ohm min.
(B46) No.20 - (B16) No.12: 0 Ohms
3. CHECK ATF TEMPERATURE SENSOR.
1) Disconnect connector from transmission.
2) Measure resistance between transmission connector receptacle's terminals.
(Connector) terminal: Specified resistance
(E19) No.5 - No.12: 2.3 - 2.7k Ohms
[ATF temperature: 20°C (68°F)
3) Connect connector to transmission, and warm up the engine to increase ATF temperature.
4) Stop the engine and disconnect connector from transmission.
5) Measure resistance between transmission connector receptacle's terminals.
(Connector) terminal: Specified resistance
(E19) No.5 - No.12: 280 - 360 Ohms
[ATF temperature: 8O°C (176°F)]