P0820 – Neutral Position Sensor System Vehicles with AS&G system MMC Colt



OPERATION

  • A power voltage of 5 V is applied to the neutral position sensor power terminal (terminal No. 3) from the engine-ECU (terminal No. 41) and earthed to the engine-ECU (terminal No. 26) from the neutral position sensor (terminal No. 4).
  • The sensor signal is inputted to the engine-ECU (terminal No. 11) from the neutral position sensor output terminal (terminal No. 1).

  • FUNCTION

  • The neutral position sensor outputs the duty signal according to the shift lever position.
  • In response to the signal, the engine-ECU controls the AS&G system.

  • TROUBLE JUDGMENT

  • 2 seconds later after the ignition switch has been in “ON” position or the engine has started up.
  • The battery voltage is more than 8 V and is less than 16 V.
  • For 2 seconds, the falling signal from the neutral position sensor is not detected.
  • For 2 seconds, the time from the neutral position sensor per cycle is lower than 3.5ms or more than 4.5 ms.

  • PROBABLE CAUSES

  • Failed neutral position sensor
  • Open or shorted neutral position sensor circuit, harness damage, or connector damage
  • Failed engine-ECU

  • DIAGNOSIS PROCEDURE

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

  • Item No. 163: Neutral position sensor
  • Q. Is the check result normal?

    STEP 2. Connector check: A-146 neutral position sensor connector

    Q. Is the check result normal?

    STEP 3. Perform voltage measurement at A-146 neutral position 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. Connector check: A-08 engine-ECU connector

    Q. Is the check result normal?

    STEP 5. Check harness between A-146 (terminal No. 3) neutral position sensor connector and A-08 (terminal No. 41) 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 No. 163: Neutral position sensor
  • Q. Is the check result normal?

    STEP 7. Perform resistance measurement at A-146 neutral position sensor 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: A-08 engine-ECU connector

    Q. Is the check result normal?

    STEP 9. Check harness between A-146 (terminal No. 4) neutral position sensor connector and A-08 (terminal No. 26) engine-ECU connector.

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

    STEP 10. Connector check: A-08 engine-ECU connector

    Q. Is the check result normal?

    STEP 11. Check harness between A-146 (terminal No. 3) neutral position sensor connector and A-08 (terminal No. 41) engine-ECU connector.

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

    STEP 12. Perform voltage measurement at A-08 engine-ECU connector.

  • Disconnect engine-ECU connector, and connect special tool power plant ECU check harness (MB991987), and then measure the voltage on the check connector.
  • Ignition switch: ON
  • Voltage between terminal No. 11 and earth.
  • Q. Is the check result normal?

    STEP 13. Check harness between A-146 (terminal No. 1) neutral position sensor connector and A-08 (terminal No. 11) engine-ECU connector.

  • Check output line for open/short circuit and damage.
  • Q. Is the check result normal?

    Author: admin