Code No.B1201: Fuel information problem



caution Before replacing the combination meter, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.


TROUBLE JUDGEMENT




PROBABLE CAUSES



  • Damaged harness wires and connectors
  • Malfunction of fuel pump and gauge unit (main)
  • Malfunction of fuel gauge unit (sub) <4WD>
  • Malfunction of combination meter

DIAGNOSIS PROCEDURE


STEP 1. Check of fuel pump and gauge unit (main) circuit


(1)Disconnect the fuel pump and gauge unit (main) connector.
(2)Use the special tool Check harness (MB991219) to connect a test lamp (12 V - 3.4 W) between the wiring harness connector terminals.
(3)Turn the ignition switch to the ON position.
(4)Check if the test lamp illuminates.
OK: Illuminates

Q. Is the check result normal?





STEP 2. Fuel pump and gauge unit (main) and fuel gauge unit (sub) check



Q. Is the check result normal?





STEP 3. Resistance measurement at the fuel pump and gauge unit (main) connector


(1)Disconnect the fuel pump and gauge unit (main) connector, the measure at the harness side.
(2)Measure the resistance between the fuel pump and gauge unit (main) connector (earth terminal) and the body earth.
OK: Continuity exists (2 Ω or less)

Q. Is the check result normal?





STEP 4. Check of open circuit (disconnect) in body earth line between fuel pump and gauge unit (main) connector and body earth.


Q. Is the check result normal?





STEP 5. Check of short to power supply circuit (connect) in F/G line between combination meter connector and fuel pump and gauge unit (main) connector.


Q. Is the check result normal?





STEP 6. M.U.T.-III actuator test



  • Item 03: Fuel gauge (target value): 0 →100%
OK: The fuel gauge operates.

Q. Is the check result normal?





STEP 7. Check whether the diagnosis code is reset.



(1)Erase the diagnosis code.
(2)Turn the ignition switch from "LOCK" (OFF) position to "ON" position.
(3)Check if diagnosis code is set.

Q. Is the diagnosis code set?