DTC P058A: Battery Monitor Module Performance: Notes

DTC detecting condition: 

Immediately at fault recognition

Failure detection pattern: 

• "Primary" (high-priority diagnosis)

Warning light/indicator light: 

• Malfunction indicator light

Wiring diagram: 

Engine Electrical System Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM>2.0 L MODEL .

Courtesy of SUBARU OF AMERICA, INC.

1. BASIC INSPECTION  .

   Before performing the diagnosis, perform basic inspection. Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.0)>GENERAL DESCRIPTION>INSPECTION .

   NOTE:

   • Check the battery and its installation condition.
   • Check the related fuse.
   • Visually check that the related connectors are properly connected.

     Also, check the related ground terminal for looseness and corrosion.

   Is the check result OK?

   Yes  : GO TO  2.

   No  : Repair the defective part.

   After the repair, GO TO  4.

2. CHECK HARNESS (OPEN CIRCUIT IN BATTERY SENSOR POWER SUPPLY LINE)  .
   1. Disconnect the connector from battery sensor.
      CAUTION: When disconnecting the connector, check for poor contact due to damage, looseness, adherence of foreign matter on the connector and terminal.
   2. Measure the resistance between the following terminals.

      Connector & terminal: Standard 

      Battery positive terminal - (B91) No. 1: Less than 1 Ω

      Battery positive terminal - (B91) No. 2: Less than 1 Ω

   Is the check result OK?

   Yes  : GO TO  3.

   No  : Repair the defective part.

   After the repair, GO TO  4.

3. CHECK BATTERY SENSOR  .
   1. Connect all connectors and terminals.
   2. Turn the ignition switch to ON. (Engine OFF)
   3. Using the Subaru Select Monitor or a general scan tool, perform the clear memory of [Engine]. Ref. to COMMON (DIAGNOSTICS)>CLEAR MEMORY .
   4. Turn the ignition switch to OFF.
   5. Leave the battery for 5 seconds or more with the battery sensor connector disconnected, and then reconnect the connector.
   6. With the ignition switch OFF, wait for at least 10 minutes.
      NOTE: In order to complete the self-diagnosis of the battery sensor, it is necessary to wait for 5 minutes or more with the standby current at 200 mA or less.
   7. Turn the ignition switch to ON (engine OFF) and wait for at least 1 minute.
   8. Using the Subaru Select Monitor, read the value in [Alternator control check 3]. If the value is 0, extend the time the vehicle has been left since ignition switch OFF in step 6 and repeat steps  4 - 8.
      NOTE: For detailed operation procedures, refer to "COMMON (DIAGNOSTICS)". Ref. to COMMON (DIAGNOSTICS)>DATA MONITOR .

      Specification: 

      [Alternator control check 3]: 0.01 - 250

      NOTE: If the value is 0, it is possible that the self-diagnosis of the battery sensor was not complete due to unstable standby current. Therefore, extend the time the vehicle has been left since ignition switch OFF in step 6 and repeat steps  4 -  8.

   Is the check result OK?

   Yes  : Replace the ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>ENGINE CONTROL MODULE (ECM) .

   After replacement, GO TO  4.

   No  : Replace the battery sensor. Ref. to STARTING/CHARGING SYSTEMS (H4DO)>BATTERY SENSOR .

   After replacement, GO TO  4.

4. CHECK REPAIR  .
   1. Perform the inspection mode corresponding to DTC. Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.0)>INSPECTION MODE>PROCEDURE .
   2. Confirm that DTC or cancel code is not stored and the malfunction is eliminated.

   Is the check result OK?

   Yes  : Finish the diagnosis.

   No  : Perform the diagnosis according to the basic diagnostic procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.0)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .