DTC P1518: Starter Switch Circuit Low: Notes

1. - 

DTC detecting condition: 

Detected when three consecutive driving cycles with fault occur.

Trouble symptom: 

Auto Start Stop does not operate.

Wiring diagram: 

• ENGINE TYPE FB

Auto Start Stop Ref. to WIRING SYSTEM>AUTO START STOP>WIRING DIAGRAM>ENGINE TYPE FB .

Courtesy of SUBARU OF AMERICA, INC.

• ENGINE TYPE FA

Auto Start Stop Ref. to WIRING SYSTEM>AUTO START STOP>WIRING DIAGRAM>ENGINE TYPE FA .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DATA MONITOR  .

   Read the data of [Starter Switch] using Subaru Select Monitor. Ref. to AUTO START STOP (DIAGNOSTICS)>DATA MONITOR .

   Is [OFF] displayed in [Starter Switch]?

   Yes:  Go to  2 .

   No:  The circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2. CHECK INPUT VOLTAGE OF TCM  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the TCM connector.
   3. Start the engine.
   4. Measure the voltage between TCM connector and chassis ground.

      Connector and terminal 

      ENGINE TYPE FB

      (T21) No. 45 (+) - Chassis ground (-):

      ENGINE TYPE FA

      (B67) No. 45 (+) - Chassis ground (-):

   Is the voltage less than 1 V?

   Yes:  Check the following item and repair if necessary.

   • Model with push button start

     Repair the open circuit of harness between keyless access CM and TCM connector.

   • Model without push button start

   Open harness between ignition switch and TCM connector

   Poor contact inside the ignition switch

   No:  Check for poor contact of TCM connector. Replace the TCM if no fault is found. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580)>TRANSMISSION CONTROL MODULE (TCM) . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>TRANSMISSION CONTROL MODULE (TCM) .