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Home >> Subaru >> 2006 >> Baja Turbo, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 16 (Automatic Transmission Diagnostics (4AT) (H4SO)) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC 27 ATF Temperature Sensor

DTC 27 ATF Temperature Sensor

WARNING: This page is about a different variant/trim than selected.

DIAGNOSIS: 

The input signal circuit of TCM to ATF temperature sensor is open or shorted.

TROUBLE SYMPTOM: 

Excessive shift shock.

WIRING DIAGRAM: 

Fig 1: ATF Temperature Sensor - Wiring Diagram
G04990729Courtesy of SUBARU OF AMERICA, INC.
DIAGNOSTIC PROCEDURE CHART

Step Check Yes No
1 CHECK HARNESS CONNECTOR BETWEEN TCM AND ATF TEMPERATURE SENSOR. 
  1. Turn the ignition switch to OFF.
  2. Disconnect the connector from transmission and TCM.
  3. Measure the resistance of harness between TCM and transmission connector.

    Connector & terminal 

    (B55) No. 10 - (B11) No. 12: 

 Is the resistance less than 1 Ω? Go to step 2.  Repair the open circuit in harness between TCM and transmission connector.
2 CHECK HARNESS CONNECTOR BETWEEN TCM AND ATF TEMPERATURE SENSOR. 
Measure the resistance of harness between TCM and transmission connector.
Connector & terminal 
(B55) No. 11 - (B11) No. 11: 		 Is the resistance less than 1 Ω? Go to step 3.  Repair the open circuit in harness between TCM and transmission connector.
3 CHECK HARNESS CONNECTOR BETWEEN TCM AND ATF TEMPERATURE SENSOR. 
Measure the resistance of harness between TCM connector and chassis ground.
Connector & terminal 
(B55) No. 10 - Chassis ground: 		 Is the resistance more than 1 MΩ? Go to step 4.  Repair the short circuit in harness between TCM and transmission connector.
4 CHECK HARNESS CONNECTOR BETWEEN TCM AND ATF TEMPERATURE SENSOR. 
Measure the resistance of harness between TCM connector and chassis ground.
Connector & terminal 
(B55) No. 11 - Chassis ground: 		 Is the resistance more than 1 MΩ? Go to step 5.  Repair the short circuit in harness between TCM and transmission connector.
5 CHECK ATF TEMPERATURE SENSOR. 
  1. Turn the ignition switch to OFF.
  2. Connect the connectors to transmission and TCM.
  3. Turn the ignition switch to ON and start engine.
  4. Warm-up the transmission until ATF temperature reaches to 80°C (176°F).
    NOTE: If ambient temperature is below 0°C (32°F), drive the vehicle until ATF reaches its operating temperature.
  5. Disconnect the connector from transmission.
  6. Measure the resistance between transmission connector terminals.

    Connector & terminal 

    (T4) No. 11 - No. 12: 

 Is the resistance 275 - 375 Ω? Go to step 6.  Replace the ATF temperature sensor. < Ref. to SHIFT SOLENOIDS, DUTY SOLENOIDS AND ATF TEMPERATURE SENSOR . >
6 CHECK ATF TEMPERATURE SENSOR. 
  1. Turn the ignition switch to ON (engine OFF).
  2. Measure the resistance between transmission connector terminals.

    Connector & terminal 

    (T4) No. 11 - No. 12: 

 Does the resistance value increase while ATF temperature decreases? Go to step 7.  Replace the ATF temperature sensor. < Ref. to SHIFT SOLENOIDS, DUTY SOLENOIDS AND ATF TEMPERATURE SENSOR . >
7 PREPARE SUBARU SELECT MONITOR.  Do you have a Subaru Select Monitor? Go to step 9.  Go to step 8. 
8 CHECK INPUT SIGNAL FOR TCM. 
  1. Connect the connector to transmission.
  2. Warm-up the transmission until ATF temperature is about 80°C (176°F).
    NOTE: If ambient temperature is below 0°C (32°F), drive the vehicle until ATF reaches its operating temperature.
  3. Measure the voltage between TCM connector terminal.

    Connector & terminal 

    (B55) No. 11 (+) - No. 10 (-): 

 Is the voltage 0.4 - 0.9 V? Even if the AT OIL TEMP warning light blinks, the circuit has returned to a normal condition at this time. Temporary poor contact of the connector or harness may be the cause. Repair the harness or contact in ATF temperature sensor and transmission connector. Go to step 10. 
9 CHECK INPUT SIGNAL FOR TCM USING SUBARU SELECT MONITOR. 
  1. Connect the connector to transmission.
  2. Turn the ignition switch to ON (engine OFF).
 Does the ATF temperature gradually decrease? Even if the AT OIL TEMP warning light blinks, the circuit has returned to a normal condition at this time. Temporary poor contact of the connector or harness may be the cause. Repair the harness or contact in ATF temperature sensor and transmission connector. Go to step 10. 
10 CHECK POOR CONTACT.  Is there poor contact in ATF temperature sensor circuit? Repair the poor contact. Replace the TCM. < Ref. to TRANSMISSION CONTROL MODULE (TCM) . >

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