Code No. B254B CAMERA output voltage fault

TROUBLE JUDGEMENT

When the camera-ECU detects any of the conditions below, the ECU sets diagnosis code No. B254B.

Power supply voltage to a camera remains 5.2 V or less for at least 5 seconds.
Power supply voltage to a camera remains 7 V or more for at least 5 seconds.

note

When diagnosis code No. B254B is set, the segment, which corresponds to a defective camera, is displayed in blue.

PROBABLE CAUSES

Malfunction of front-view camera
Malfunction of rear-view camera
Malfunction of side-view camera (LH)
Malfunction of side-view camera (RH)
Malfunction of camera-ECU
Damaged harness wires and connectors (power supply lines to a camera short to power supply or earth)

DIAGNOSIS PROCEDURE

STEP 1. Voltage measurement at camera connectors (ACCN, ACCR, ACCS and ACCY terminals)

(1)Disconnect the all camera connectors, and measure at the wiring harness side.

(2)Turn on the power supply mode, and then check the power supply lines to a relevant camera.
..... Check the voltage between the front-view camera connector (ACCN terminal) and body earth.
OK: 5.5 - 6.5 V
..... Check the voltage between the rear-view camera connector (ACCR terminal) and body earth.
OK: 5.5 - 6.5 V
..... Check the voltage between the side-view camera (LH) connector (ACCS terminal) and body earth.
OK: 5.5 - 6.5 V
..... Check the voltage between the side-view camera (RH) connector (ACCY terminal) and body earth.
OK: 5.5 - 6.5 V

Q. Is the check result normal?

Go to Step 3.

Go to Step 2.

STEP 2. Check of short to earth circuit in ACCN, ACCR, ACCS and ACCY lines between camera connectors and camera-ECU connector.

(1)Disconnect the all camera connectors and camera-ECU connector, and measure at the wiring harness side.
..... Measure the resistance between the front-view camera connector (ACCN terminal) and body earth.
OK: No continuity
..... Measure the resistance between the front-view camera connector (ACCN terminal) and camera-ECU connector (except ACCN terminal).
OK: No continuity
..... Measure the resistance between the rear-view camera connector (ACCR terminal) and body earth.
OK: No continuity
..... Measure the resistance between the rear-view camera connector (ACCR terminal) and camera-ECU connector (except ACCR terminal).
OK: No continuity
..... Measure the resistance between the side-view camera (LH) connector (ACCS terminal) and body earth.
OK: No continuity
..... Measure the resistance between the side-view camera (LH) connector (ACCS terminal) and camera-ECU connector (except ACCS terminal).
OK: No continuity
..... Measure the resistance between the side-view camera (RH) connector (ACCY terminal) and body earth.
OK: No continuity
..... Measure the resistance between the side-view camera (RH) connector (ACCY terminal) and camera-ECU connector (except ACCY terminal).
OK: No continuity

Q. Is the check result normal?

Replace the camera-ECU (Refer to

Repair the connector(s) or wiring harness.

STEP 3. Voltage measure at camera-ECU connector (ACCN, ACCR, ACCS and ACCY terminals)

(1)Connect camera connectors one after the other, and then measure at the power supply terminal of the corresponding camera-ECU connector by backprobing.

(2)Turn on the power supply mode.

(3)Connect the front-view camera connector.

(4)Check the voltage between camera-ECU connector (ACCN terminal) and body earth.
OK: 5.5 - 6.5 V

(5)Connect the rear-view camera connector.

(6)Check the voltage between camera-ECU connector (ACCR terminal) and body earth.
OK: 5.5 - 6.5 V

(7)Connect the side-view camera (LH) connector.

(8)Check the voltage between camera-ECU connector (ACCS terminal) and body earth.
OK: 5.5 - 6.5 V

(9)Connect the side-view camera (RH) connector.

(10)Check the voltage between camera-ECU connector (ACCY terminal) and body earth.
OK: 5.5 - 6.5 V

Q. Is the check result normal?

Go to Step 4.

Replace the failure camera (Refer to

STEP 4 Diagnosis code recheck

Check again if the diagnosis code is set in the camera-ECU.

(1)Erase the diagnosis code.

(2)Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.

(3)Check if the diagnosis code is set.

Q. Is the diagnosis code set?

Replace the camera-ECU (Refer to

The procedure is complete.