DTC P0842 Secondary Oil Pressure Sensor Circuit (Low): Wiring Diagram

Fig 1: Secondary Oil Pressure Sensor - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK INPUT SIGNAL FOR TCM.  Start the engine. Warm up until the ATF temperature reaches to 40 - 70°C (104 - 158°F). Shift the select lever to "P" range. Stabilize the engine speed at idle. Read the data of "Actual secondary pressure" using Subaru Select Monitor.	Is "Actual secondary pressure" 0.5 - 1.5 MPa?	Check for poor contact of connector.	Go to step 2  .
2 CHECK HARNESS.  Turn the ignition switch to OFF. Disconnect the TCM and transmission connectors. Measure the resistance between TCM connector and transmission connectors. Connector & terminal  (B54) No. 2 - (B11) No. 17:  (B54) No. 15 - (B11) No. 18:  (B54) No. 17 - (B11) No. 14:	Is the resistance less than 1 Ω?	Go to step 3  .	Repair the open circuit of harness.
3 CHECK HARNESS.  Measure the resistance between TCM connector and chassis ground. Connector & terminal  (B54) No. 2 - Chassis ground:  (B54) No. 17 - Chassis ground:	Is the resistance 1 MΩ or more?	Go to step 4  .	Repair the short circuit of harness.
4 CHECK TRANSMISSION HARNESS.  Disconnect the secondary pressure sensor connector. Measure the resistance between transmission connector and secondary pressure sensor connector. Connector & terminal  (T4) No. 14 - (AT6) No. 2:  (T4) No. 17 - (AT6) No. 1:  (T4) No. 18 - (AT6) No. 3:	Is the resistance less than 1 Ω?	Go to step 5  .	Repair the open circuit of harness.
5 CHECK TRANSMISSION HARNESS.  Measure the resistance between transmission connector and chassis ground. Connector & terminal  (T4) No. 14 - Chassis ground:  (T4) No. 17 - Chassis ground:	Is the resistance 1 MΩ or more?	Go to step 6  .	Repair the short circuit of harness.
6 CHECK SENSOR POWER SUPPLY.  Connect the connectors of TCM and transmission. Turn the ignition switch to ON. Measure the voltage between secondary pressure sensor connector terminals. Connector & terminal  (AT6) No. 1 (+) - (AT6) No. 3 (-):	Is the voltage 4.5 V or more?	Replace the secondary pressure sensor. Ref. to SECONDARY PRESSURE SENSOR .	Check for poor contact of the connector, and repair the fault location.