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Subaru Legacy Service Manual: Dtc b2902 rear height sensor circuit

DTC DETECTING CONDITION:

Rear vehicle height sensor error is detected for 10 seconds or more.

TROUBLE SYMPTOM:

The auto headlight beam leveler does not operate.

CAUTION:

Initialization is required after replacing the auto headlight beam leveler CM.

WIRING DIAGRAM:

NOTE:

For the coupling connector, refer to “WIRING SYSTEM”.

Headlight beam leveler system Headlight Beam Leveler System > WIRING DIAGRAM

STEPCHECKYESNO

1.CHECK DTC.

1) Turn the ignition switch to OFF > ON.

2) Turn on the headlight low beam.

3) Using the Subaru Select Monitor, clear the auto headlight beam leveler system memory. Clear Memory Mode

4) Use the Subaru Select Monitor and read DTCs. Read Diagnostic Trouble Code (DTC)

Is DTC B2902 displayed- (current malfunction)

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B2902 REAR HEIGHT SENSOR CIRCUIT

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 CURRENT DATA.

Display «R Sensor Signal» using Subaru Select Monitor. Read Current Data

Does the data indicate the standard value (approx. 2.5 V when on a level road with one person in the vehicle)-

Replace the auto headlight beam leveler CM. Auto Headlight Beam Leveler Control Module

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B2902 REAR HEIGHT SENSOR CIRCUIT

3.CHECK CURRENT DATA.

1) Display «R Sensor Signal» using Subaru Select Monitor. Read Current Data

2) Change the vehicle posture.

Does the data change-

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B2902 REAR HEIGHT SENSOR CIRCUIT

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B2902 REAR HEIGHT SENSOR CIRCUIT

4.CHECK OUTPUT VOLTAGE BETWEEN AUTO HEADLIGHT BEAM LEVELER CM AND VEHICLE HEIGHT SENSOR.

1) Disconnect the vehicle height sensor connector.

2) Turn the ignition switch to ON.

3) Measure the voltage between the vehicle height sensor connector and chassis ground.

Connector & terminal

(R29) No. 3 (+) — Chassis ground (−):

Is the voltage 5±0.25 V-

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B2902 REAR HEIGHT SENSOR CIRCUIT

Replace the auto headlight beam leveler CM. Auto Headlight Beam Leveler Control Module

5.CHECK REAR HEIGHT SENSOR.

1) Remove the rear vehicle height sensor.

2) Perform the inspection of rear height sensor unit. Rear Height Sensor > INSPECTION

Is the rear height sensor normal-

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B2902 REAR HEIGHT SENSOR CIRCUIT

Replace the rear height sensor. Rear Height Sensor

6.CHECK HARNESS (OPEN CIRCUIT).

1) Disconnect the auto headlight beam leveler CM connector.

2) Using a tester, measure the resistance between the auto headlight beam leveler CM connector and rear height sensor connector.

Connector & terminal

(B150) No. 3 — (R29) No. 1:

(B150) No. 19 — (R29) No. 2:

(B150) No. 12 — (R29) No. 3:

Is there continuity-

Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC B2902 REAR HEIGHT SENSOR CIRCUIT

Repair or replace the open circuit of harness.

7.CHECK HARNESS (GROUND SHORT CIRCUIT).

Using a tester, measure the resistance between the auto headlight beam leveler CM connector and chassis ground.

Connector & terminal

(B150) No. 3 — Chassis ground:

(B150) No. 19 — Chassis ground:

(B150) No. 12 — Chassis ground:

Is the resistance 10 k- or more-

Replace the auto headlight beam leveler CM. Auto Headlight Beam Leveler Control Module

Repair or replace the short circuit of the harness.

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DTC DETECTING CONDITION:Detected when internal malfunction occurs in the auto headlight beam leveler CM.TROUBLE SYMPTOM:The auto headlight beam leveler does not operate.CAUTION:Initialization is requi ...

Other materials:

Inspection
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