Posted in MMC L200

P0122 – Throttle Position Sensor Circuit Low Input MMC L200 IV

 Posted by  Posted on September 28, 2020

OPERATION

  • A power voltage of 5 V is applied to the electronic-controlled throttle valve (terminal No. 2) from the engine-ECU (terminal No. 93).
  • The power voltage is earthed to the engine-ECU (terminal No. 34) from the electronic-controlled throttle valve (terminal No. 4).
  • The sensor signal is inputted to the engine-ECU (terminal No. 40) from the electronic-controlled throttle valve output terminal (terminal No. 1).

    • FUNCTION

  • The throttle position sensor converts the throttle valve position into voltage and inputs it into the engine-ECU.
  • The engine-ECU control the throttle valve position.

    • 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 throttle position sensor output voltage is 0.15 V or less for 0.5 second.

    • PROBABLE CAUSES

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

    • DIAGNOSIS PROCEDURE

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

  • Item 45: Throttle position sensor

    • Q. Is the check result normal?

    STEP 2. Connector check: A-132 electronic-controlled throttle valve connector

    Q. Is the check result normal?

    STEP 3. Perform voltage measurement at A-132 electronic-controlled throttle valve connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 2 and earth.

    • Q. Is the check result normal?

    STEP 4. Connector check: C-105 engine-ECU connector

    Q. Is the check result normal?

    STEP 5. Check harness between A-132 (terminal No. 2) electronic-controlled throttle valve connector and C-105 (terminal No. 93) engine-ECU connector.

  • Check power supply line for open/short circuit.

    • Q. Is the check result normal?

    STEP 6. M.U.T.-III data list

  • Item 45: Throttle position sensor

    • Q. Is the check result normal?

    STEP 7. Perform resistance measurement at A-132 electronic-controlled throttle valve connector.

  • Disconnect connector, and measure at harness side.
  • Resistance between terminal No. 4 and earth.

    • Q. Is the check result normal?

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

    Q. Is the check result normal?

    STEP 9. Check harness between A-132 (terminal No. 4) electronic-controlled throttle valve connector and C-105 (terminal No. 34) engine-ECU connector.

  • Check earthing line for damage.

    • Q. Is the check result normal?

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

    Q. Is the check result normal?

    STEP 11. Perform voltage measurement at A-132 electronic-controlled throttle valve 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 12. Connector check: C-105 engine-ECU connector

    Q. Is the check result normal?

    STEP 13. Check harness between A-132 (terminal No. 1) electronic-controlled throttle valve connector and C-105 (terminal No. 40) engine-ECU connector.

  • Check output line for short circuit.

    • Q. Is the check result normal?

    STEP 14. Check harness between A-132 (terminal No. 2) electronic-controlled throttle valve connector and C-105 (terminal No. 93) engine-ECU connector.

  • Check power supply line for damage.

    • Q. Is the check result normal?

    STEP 15. Check harness between A-132 (terminal No. 1) electronic-controlled throttle valve connector and C-105 (terminal No. 40) engine-ECU connector.

  • Check output line for open circuit and damage.

    • Q. Is the check result normal?

    Author: admin