P0192 – Rail Pressure Sensor Circuit Low Input MMC L200 IV



OPERATION

  • A power voltage of 5 V is applied to the rail pressure sensor power terminal (terminal No. 1) from the engine-ECU (terminal No. 70) and earthed to the engine-ECU (terminal No. 88) from the rail pressure sensor (terminal No. 3).
  • The sensor signal is inputted to the engine-ECU (terminal No. 64) from the rail pressure sensor output terminal (terminal No. 2).

  • FUNCTION

  • The rail pressure sensor converts the rail pressure into a voltage signal and inputs the signal to the engine-ECU.
  • In response to the signal, the engine-ECU corrects the fuel injection quantity.

  • 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 rail pressure sensor output voltage is 0.70 V or less for 0.5 second.

  • PROBABLE CAUSES

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

  • DIAGNOSIS PROCEDURE

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

  • Item 63: Rail pressure sensor
  • Q. Is the check result normal?

    STEP 2. Connector check: A-44 rail pressure sensor connector

    Q. Is the check result normal?

    STEP 3. Perform voltage measurement at A-44 rail pressure sensor connector.

  • Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness.
  • Ignition switch: ON
  • Voltage between terminal No. 1 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. 70 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-44 (terminal No. 1) rail pressure sensor connector and C-105 (terminal No. 70) 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 63: Rail 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 and damage.
  • STEP 9. Perform resistance measurement at A-44 rail pressure sensor connector.

  • Disconnect connector, and measure at harness side.
  • Resistance between terminal No. 3 and earth.
  • Q. Is the check result normal?

    STEP 10. Connector check: C-105 engine-ECU connector

    Q. Is the check result normal?

    STEP 11. Check harness between A-44 (terminal No. 3) rail pressure sensor connector and C-105 (terminal No. 88) engine-ECU connector.

  • Check earthing line for damage.
  • Q. Is the check result normal?

    STEP 12. Perform voltage measurement at A-44 rail pressure sensor connector.

  • Use special tool test harness (MB991658) to connect connector, and measure at pick-up harness.
  • Engine: Idle (after warning up)
  • Voltage between terminal No. 2 and earth.
  • Q. Is the check result normal?

    STEP 13. Connector check: C-105 engine-ECU connector

    Q. Is the check result normal?

    STEP 14. Check harness between A-44 (terminal No. 2) rail pressure sensor connector and C-105 (terminal No. 64) engine-ECU connector.

  • Check output line for short circuit.
  • Q. Is the check result normal?

    STEP 15. Perform voltage measurement at C-105 engine-ECU connector.

  • Measure engine-ECU terminal voltage.
  • Engine: Idle (after warning up)
  • Voltage between terminal No. 64 and earth.
  • Q. Is the check result normal?

    STEP 16. Connector check: C-105 engine-ECU connector

    Q. Is the check result normal?

  • Check output line for open circuit and damage.
  • STEP 17. Connector check: C-105 engine-ECU connector

    Q. Is the check result normal?

    Author: admin