DTC P1A20: Dc/Dc Converter 1 Boost Performance: Notes

DTC detecting condition: 

Detected when two consecutive driving cycles with fault occur.

Trouble symptom: 

• Auto Start Stop does not operate.
• When the Auto Start Stop restarts, the audio or navigation system is reset.

1. CHECK FOR ANY OTHER DTC ON DISPLAY  .

   Is any other DTC displayed?

   Yes:  Perform the diagnosis according to the DTC. Ref. to AUTO START STOP (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

   No:  Go to  2.

2. CHECK REPEATABILITY  .
   1. Using the Subaru Select Monitor, perform the clear memory. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
   2. Using the Subaru Select Monitor, perform [Engine stop control] in the active test to stop the engine. Ref. to AUTO START STOP (DIAGNOSTICS)>ACTIVE TEST .
      CAUTION: Do not release the brake pedal to prevent sudden acceleration of the vehicle.
   3. Operate the Auto Start Stop cancel switch to restart the engine.
   4. Turn the ignition switch to OFF and wait for 10 seconds.
   5. Using the Subaru Select Monitor, read the DTC after repeating the procedure from step  2 to  4 two times. Ref. to AUTO START STOP (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is the same DTC as current diagnosis output?

   Yes:  Check for the poor contact of DC/DC converter 1 connector. Replace the DC/DC converter 1 if no fault is found. Ref. to STARTING/CHARGING SYSTEMS (H4DO)>AUTO START STOP DC/DC CONVERTER .

   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.