Subaru Crosstrek Service Manual: Dtc b28b6 pre-collision off switch

Detected when pre-collision brake OFF switch circuit is not installed, open-circuited or is stuck to ON.

DTC detecting condition:

• Wiring of pre-collision brake OFF switch is not connected.

• Pre-collision brake OFF switch circuit is open.

• Pre-collision brake OFF switch circuit stays ON for 45 seconds or more.

1.CHECK CURRENT DATA.

Confirm the current data «Pre-Collision Brake OFF SW Status (BIU)» of EyeSight using Subaru Select Monitor. Read Current Data">

Does the display change according to ON/OFF operation of the pre-collision brake OFF switch?

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, or temporary open or short circuit of harness may be the cause.

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B28B6 PRE-COLLISION OFF SWITCH">Go to Step 2.

2.CHECK HARNESS.

1) Disconnect the stereo camera connector and the pre-collision brake OFF switch connector.

2) Using the tester, measure the resistance between the stereo camera connector and pre-collision brake OFF switch connector as well as chassis ground.

Connector & terminal

(R406) No. 3 — (R137) No. 12:

(R406) No. 5 — Chassis ground:

Is the resistance less than 1 ??

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B28B6 PRE-COLLISION OFF SWITCH">Go to Step 3.

Repair or replace an open circuit in harness between the stereo camera connector and pre-collision brake OFF switch connector.

3.CHECK HARNESS.

Using the tester, measure the resistance between the pre-collision brake OFF switch connector and chassis ground.

Connector & terminal

(R406) No. 3 — Chassis ground:

Is the resistance 1 M? or more?

Check the pre-collision brake OFF switch. Switches and Harness > INSPECTION">

Repair or replace the short circuit to ground in harness between the stereo camera connector and pre-collision brake OFF switch connector.

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