C1251

DTC C1251: Coupling Air Temperature Sensor Circuit Short

Wiring Diagram

Refer to C1250 DTC C1250: Coupling Air Temperature Sensor Circuit Open.

DTC Detecting Condition and Trouble Area






DTC Confirmation Procedure

1) Clear DTC using scan tool.
2) Turn ignition switch to ON position for 10 seconds.
3) Check DTC.

Troubleshooting



1.
Was "4WD control system check" performed?
YES
Go to Step 2.
NO
Go to 4WD Control System Check.

2. Coupling air temperature sensor circuit check

Disconnect connector from coupling air temperature sensor with ignition switch turned OFF.
Check for proper connection to "YEL/BLK" and "BLU/WHT" terminals of coupling air temperature sensor connector.
If connection is OK, measure voltage between "YEL/BLK" terminal of coupling air temperature sensor connector and vehicle body ground with ignition switch turned ON.

Is it 4 - 6 V?
YES
Go to Step 3.
NO
Go to Step 5.

3. Coupling assembly ground circuit check

Disconnect connector from 4WD control module with ignition switch turned OFF.
Measure resistance between "BLU/WHT" terminal of coupling air temperature sensor connector and "G26-24" terminal of 4WD control module connector with ignition switch turned OFF.

Is resistance above 1 Mohms?
YES
Go to Step 4.
NO
"BLU/WHT" wire is shorted to ground circuit.

4. Coupling air temperature sensor check

Check coupling air temperature sensor referring to Coupling Air Temperature Sensor Inspection.

Is it in good condition?
YES
Substitute a known-good 4WD control module and recheck.
NO
Replace coupling air temperature sensor.

5. Coupling assembly circuit check

Disconnect connector from 4WD control module with ignition switch turned OFF.
Check for proper connection to "G26-25" and "G26-24" terminals of 4WD control module connector.
If connection is OK, measure resistance between "G26-25" terminal of 4WD control module connector and vehicle body ground.

Is resistance above 1 Mohms?
YES
"YEL/BLK" wire is shorted to ground circuit.
NO
Substitute a known-good 4WD control module and recheck.