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DTC B254B: CAMERA output voltage fault
 
 
 
 
TROUBLE JUDGMENT
When the camera-ECU detects any of the conditions below, the ECU sets DTC B254B.
  • Power supply voltage to a camera remains 5.2 volts or less for at least 5 seconds.
  • Power supply voltage to a camera remains 7 volts or more for at least 5 seconds.
noteWhen DTC B254B is set, the segment, which corresponds to a defective camera, is displayed in blue.
 
 
TROUBLESHOOTING HINTS
  • The front-view camera may be defective
  • The rear-view camera may be defective
  • The side-view camera (LH) may be defective
  • The side-view camera (RH) may be defective
  • The camera-ECU may be defective
  • Damaged harness wires and connectors (power supply lines to a camera short to power supply or ground)
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
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 the ignition switch to "ON" position, and then check the power supply lines to a relevant camera.
(1) Check the voltage between the front-view camera connector (ACCN terminal) and body ground.
OK: 5.5 - 6.5 volts
(2) Check the voltage between the rear-view camera connector (ACCR terminal) and body ground.
OK: 5.5 - 6.5 volts
(3) Check the voltage between the side-view camera (LH) connector (ACCS terminal) and body ground.
OK: 5.5 - 6.5 volts
(4) Check the voltage between the side-view camera (RH) connector (ACCY terminal) and body ground.
OK: 5.5 - 6.5 volts
Is the check result normal?
Go to Step 3.
Go to Step 2.
 
STEP 2. Resistance measurement at camera connectors (ACCN, ACCR, ACCS and ACCY terminals).
(1) Disconnect the all camera connectors and camera-ECU connector, and measure at the wiring harness side.
(2) Check of short to ground circuit in power supply lines between camera connectors and camera-ECU connector.
(1) Measure the resistance between the front-view camera connector (ACCN terminal) and body ground.
OK: No continuity
(2) Measure the resistance between the front-view camera connector (ACCN terminal) and camera-ECU connector (except ACCN terminal).
OK: No continuity
(3) Measure the resistance between the rear-view camera connector (ACCR terminal) and body ground.
OK: No continuity
(4) Measure the resistance between the rear-view camera connector (ACCR terminal) and camera-ECU connector (except ACCR terminal).
OK: No continuity
(5) Measure the resistance between the side-view camera (LH) connector (ACCS terminal) and body ground.
OK: No continuity
(6) Measure the resistance between the side-view camera (LH) connector (ACCS terminal) and camera-ECU connector (except ACCS terminal).
OK: No continuity
(7) Measure the resistance between the side-view camera (RH) connector (ACCY terminal) and body ground.
OK: No continuity
(8) Measure the resistance between the side-view camera (RH) connector (ACCY terminal) and camera-ECU connector (except ACCY terminal).
OK: No continuity
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 the ignition switch to "ON" position.
(3) Connect the front-view camera connector.
(4) Check the voltage between camera-ECU connector (ACCN terminal) and body ground.
OK: 5.5 - 6.5 volts
(5) Connect the rear-view camera connector.
(6) Check the voltage between camera-ECU connector (ACCR terminal) and body ground.
OK: 5.5 - 6.5 volts
(7) Connect the side-view camera (LH) connector.
(8) Check the voltage between camera-ECU connector (ACCS terminal) and body ground.
OK: 5.5 - 6.5 volts
(9) Connect the side-view camera (RH) connector.
(10) Check the voltage between camera-ECU connector (ACCY terminal) and body ground.
OK: 5.5 - 6.5 volts
Is the check result normal?
Go to Step 4.
Replace the failure camera (Refer to ).
 
STEP 4 Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Check again if the DTC is set in the camera-ECU.
(1) Erase the DTC.
(2) Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(3) Check the DTC.
Is the DTC set?
Replace the camera-ECU (Refer to ).
The procedure is complete.