Code No. U1201: Vehicle Speed Signal Error


FUNCTION



  • The AS&G-ECU checks for an abnormal signal of the Engine-ECU.

TROUBLE JUDGMENT


Check Conditions
  • 2 seconds later after the ignition switch has been in "ON" position or the engine has started up.
  • The diagnosis code U0100 is not detected.
Judgement Criterion
  • The vehicle speed CAN reception signal is abnormal.

FAIL-SAFE AND BACKUP FUNCTION



  • In the normal operation, the auto stop is prohibited. If the malfunction is detected during the auto stop, carry out the forcible auto start.

PROBABLE CAUSES



  • Failed harness and connector
  • Failed Engine-ECU
  • Failed AS&G-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

  • Confirm the diagnosis code is set from the Engine-ECU.

Q. Is the diagnosis code set?
Perform troubleshooting of the Engine-ECU (Refer to GROUP 13C - Troubleshooting - Inspection Chart for Diagnosis Code <4J1>, Refer to GROUP 13D - Troubleshooting - Inspection Chart for Diagnosis Code <4N1>).
Go to Step 2.

STEP 2. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?
Replace the AS&G-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).