1.CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from transmission and TCM.
3) Measure the resistance of harness between TCM connector and transmission connector.
Connector & terminal
(B54) No. 5 — (B11) No. 6:
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Is the resistance less than 1 Ω?
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Repair the open circuit of harness between TCM and transmission connector.
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2.CHECK HARNESS CONNECTOR BETWEEN TCM AND CHASSIS GROUND.
Measure the resistance of harness between TCM connector and chassis ground.
Connector & terminal
(B54) No. 5 — Chassis ground:
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Is the resistance 1 MΩ or more?
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Repair the short circuit of harness between TCM and transmission connector.
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3.CHECK LOW & REVERSE DUTY SOLENOID.
Measure the resistance between transmission connector terminals.
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Is the resistance between 2.0 — 6.0 Ω?
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4.CHECK OUTPUT SIGNAL FROM TCM USING SUBARU SELECT MONITOR.
1) Connect all connectors.
2) Connect the Subaru Select Monitor to the data link connector.
4) Run the Subaru Select Monitor.
5) Warm-up the transmission until the ATF temperature exceeds approximately 80°C (176°F).
NOTE:
If the ambient temperature falls below 0°C (32°F), drive the vehicle until the ATF reaches its operating temperature.
7) Turn the ignition switch to ON.
8) Set the select lever to “N” range.
9) Read the data of “L&R/B duty ratio” using Subaru Select Monitor.
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Is the measured value 100%?
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5.CHECK OUTPUT SIGNAL FROM TCM USING SUBARU SELECT MONITOR.
2) Shift the select lever to manual mode, and then hold it on 1st. Slowly increase the vehicle speed up to 15 km/h (9 MPH), and then return the accelerator pedal.
NOTE:
The speed difference between front and rear wheels lights the ABS warning light or the VDC warning light, but this does not indicate a malfunction. If the warning light is illuminated, clear the ABS and VDC memories of the on-board diagnostic system after completing AT control diagnosis. 
3) Read the data of the low & reverse duty solenoid.
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Is the measured value 55%?
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The circuit is normal. If the ATF temperature warning light is flashing, repair the harnesses or connectors between TCM and transmission.
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Is there poor contact in the low & reverse duty solenoid circuit?
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Replace the TCM. 
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7.CHECK LOW & REVERSE BRAKE DUTY SOLENOID (IN TRANSMISSION).
1) Remove the transmission connector from bracket.
2) Drain the automatic transmission fluid.
CAUTION:
Do not drain ATF until it cools down.
3) Remove the oil pan, and disconnect the connector from control valve body.
4) Measure the resistance between low & reverse duty solenoid connector and transmission ground.
Connector & terminal
(AT2) No. 1 — Transmission ground:
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Is the resistance between 2.0 — 6.0 Ω?
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Replace the control valve body. 
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8.CHECK HARNESS CONNECTOR BETWEEN TRANSMISSION AND LOW & REVERSE DUTY SOLENOID.
Measure the resistance of harness between low & reverse duty solenoid and transmission connector.
Connector & terminal
(T4) No. 6 — (AT2) No. 1:
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Is the resistance less than 1 Ω?
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Repair open circuit of harness between low & reverse duty solenoid and transmission connector.
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9.CHECK HARNESS CONNECTOR BETWEEN TRANSMISSION AND LOW & REVERSE DUTY SOLENOID.
Measure the resistance of harness between transmission connector and transmission ground.
Connector & terminal
(T4) No. 6 — Transmission ground:
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Is the resistance 1 MΩ or more?
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The circuit is normal. If the ATF temperature warning light is flashing, repair the harnesses or connectors between low & reverse duty solenoid and transmission.
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Repair the short circuit of the harness between the low & reverse duty solenoid and the transmission connector.
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