DTC P0638 – ThrottleValve Control Servo Circuit Range-Performance Problem MMC Colt



OPERATION

  • Controls the current that is applied from the engine-ECU (terminal No. 7 and No. 22) to the electronic-controlled throttle valve (terminals No. 1 and No. 2).
  • The engine-ECU (terminal No. 93 and No. 108 is earthed to the vehicle body)

  • FUNCTION

  • Engine-ECU checks the electronic-controlled throttle system for abnormal conditions.

  • TROUBLE JUDGMENT

  • Battery positive voltage is 8.3 V or higher.
  • Throttle position sensor (main) output voltage is 0.35 – 4.8 V.
  • Drop of throttle position sensor (main) output voltage per 100 milliseconds is 0.04 V or more.
  • Throttle position sensor (main) output voltage has continued to be above 0.5 V higher than the target throttle position sensor (main) voltage for 0.5 second.
  • Battery positive voltage is 8.3 V or higher.
  • Throttle position sensor (main) output voltage is 0.35 – 4.8 V.
  • Difference between throttle position sensor (main) output voltage and target throttle position sensor (main) voltage is 1 V or higher for 4 seconds.

  • PROBALE CAUSES

  • Failed throttle valve operation.
  • Failed throttle valve control servo.
  • Open or shorted throttle valve control servo circuit, harness damage, or connector damage
  • Failed engine-ECU

  • DIAGNOSIS PROCEDURE

    STEP 1. Check the throttle valve control servo itself.

    Q. Is the check result normal?

    STEP 2. Connector check: A-118 electronic-controlled throttle valve connector and A-08 engine-ECU connector.

    Q. Is the check result normal?

    STEP 3. Perform resistance measurement at A-09 engine-ECU connector.

  • Disconnect connector, and measure at harness side.
  • Resistance between terminal No. 93 and earth, also between or terminal No. 108 and earth.
  • Q. Is the check result normal?

  • Check and repair harness between A-08 (terminal No. 93) engine-ECU connector and body earth.
  • Check and repair harness between A-08 (terminal No. 108) engine-ECU connector and body earth.
  • STEP 4. Check harness between A-118 (terminal No. 1) electronic-controlled throttle valve connector and A-08 (terminal No. 7) engine-ECU connector.

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

    STEP 5. Check harness between A-118 (terminal No. 2) electronic-controlled throttle valve connector and A-08 (terminal No. 22) engine-ECU connector.

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

    STEP 6. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.
  • Q. Is the diagnosis code set?

    Author: admin