Posted in MMC L200

P2454 – Exhaust Differential Pressure Sensor Circuit Low Input Euro5b MMC L200 IV

 Posted by  Posted on September 30, 2020

OPERATION

  • A power voltage of 5 V is applied to the exhaust differential pressure sensor power terminal (terminal No. 3) from the engine-ECU (terminal No. 94) and earthed to the engine-ECU (terminal No. 80) from exhaust differential pressure sensor (terminal No. 2).
  • The sensor signal is inputted to the engine-ECU (terminal No. 56) from the exhaust differential pressure sensor output terminal (terminal No. 1).

    • FUNCTION

  • The exhaust differential pressure sensor outputs the voltage to the engine-ECU in accordance with the difference in the voltage between the DPF upstream area and the DPF downstream area.
  • The engine-ECU anticipates the amount of PM accumulated in the DPF through this output voltage.

    • TROUBLE JUDGMENT

  • Battery positive voltage is 8 – 16 V
  • 2 seconds later after the ignition switch has been in “ON” position or the engine has started up
  • The exhaust differential pressure sensor output voltage is 0.49 V or less.

    • PROBABLE CAUSES

  • Failed exhaust differential pressure sensor
  • Open/short circuit or harness damage in exhaust differential pressure sensor circuit or loose connector contact
  • Failed engine-ECU

    • DIAGNOSTIC PROCEDURE

    STEP 1. M.U.T.-III data list

  • Item 120: exhaust differential pressure sensor

    • Q. Is the check result normal?

    STEP 2. Connector check: A-148 exhaust differential pressure sensor connector

    Q. Is the check result normal?

    STEP 3. Perform voltage measurement at A-148 exhaust differential pressure sensor connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 3 and earth.

    • Q. Is the check result normal?

    STEP 4. Perform voltage measurement at C-105 engine-ECU connector.

  • Measure engine-ECU terminal voltage.
  • Ignition switch: ON
  • Voltage between terminal No. 94 and earth.

    • Q. Is the check result normal?

    STEP 5. Connector check: C-105 engine-ECU connector

    Q. Is the check result normal?

    STEP 6. Check harness between A-148 (terminal No. 3) exhaust differential pressure sensor connector and C-105 (terminal No. 94) engine-ECU connector.

  • Check power supply line for short circuit.

    • Q. Is the check result normal?

    STEP 7. M.U.T.-III data list

  • Item 120: exhaust differential pressure sensor

    • Q. Is the check result normal?

    STEP 8. Connector check: C-105 engine-ECU connector

    Q. Is the check result normal?

  • Check power supply line for open circuit.

    • STEP 9. Connector check: C-105 engine-ECU connector

    Q. Is the check result normal?

    STEP 10. Check harness between A-148 (terminal No. 3) exhaust differential pressure sensor connector and C-105 (terminal No. 94) engine-ECU connector.

  • Check power supply line for damage.

    • Q. Is the check result normal?

    STEP 11. Check harness between A-148 (terminal No. 1) exhaust differential pressure sensor connector and C-105 (terminal No. 56) engine-ECU connector.

  • Check output line for open/short circuit and damage.

    • Q. Is the check result normal?

    STEP 12. Replace the exhaust differential pressure sensor

    Q. Is the check result normal?

    Author: admin