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Home >> Subaru >> 2017 >> WRX STI >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Anti-Theft Systems >> Security And Locks - Keyless Access (W/ Push Button Start) (Diagnostics) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC B278D Id Code Box Judgment Circuit
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DTC B278D Id Code Box Judgment Circuit

DTC DETECTING CONDITION: 

TROUBLE SYMPTOM: 

Engine will not start.

CAUTION: For replacement procedure of Keyless Access Control Module, refer to the "REGISTRATION MANUAL FOR IMMOBILIZER" provided as a separate volume.

WIRING DIAGRAM: 

Push button start system <Ref. to WIRING DIAGRAM , Push Button Start System.>

Fig 1: ID Code Box Judgment Circuit - Wiring Diagram
G10271479Courtesy of SUBARU OF AMERICA, INC.
Step Check Yes No
1 CHECK DTC. 
  1. Turn the ignition switch to OFF.
  2. Using the Subaru Select Monitor, clear the keyless access system memory. <Ref. to CLEAR MEMORY MODE .>
  3. Turn the ignition switch to OFF → ON.
  4. Read the DTC using Subaru Select Monitor. <Ref. to READ DIAGNOSTIC TROUBLE CODE (DTC) .>
Is DTC B278D displayed? Go to step . Even if DTC is displayed, 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 HARNESS (GROUND SHORT CIRCUIT). 
  1. Disconnect the Keyless Access Control Module connector.
  2. Measure the resistance between Keyless Access Control Module connector and chassis ground.

Connector & terminal 
(B573) No. 15 - Chassis ground: 
Is the resistance 10 kΩ or more? Replace the Keyless Access Control Module. <Ref. to Keyless Access Control Module .> Repair or replace the short circuit of the harness.