Code No. P0606: Engine-ECU main processor malfunction








OPERATION



  • Refer to Inspection Procedure 20: Engine-ECU Power Supply, Engine Control Relay, Ignition Switch-IG1 System

FUNCTION



  • The engine-ECU check whether the microcomputer, which performs the drive control of the throttle valve, is normal.

TROUBLE JUDGMENT


Check Condition
  • Ignition switch is "ON" position.
Judgement Criterion
  • No surveillance pulse signals should be input.

FAIL-SAFE AND BACKUP FUNCTION



  • Throttle opening degree position is in default position.

PROBABLE CAUSES



  • Failed engine control relay
  • Short circuit in the engine control relay circuit or loose connector contact.
  • Open/short circuit or harness damage in the ignition switch (IG) circuit or loose connector contact.
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check battery.

  • Battery check (Refer to GROUP 54A - Battery - On-vehicle Service - Battery Test ).

Q. Is the check result normal?
Go to Step 2 .
Replace the battery.

STEP 2. Connector check: B-09 engine-ECU connector

Q. Is the check result normal?
Go to Step 3 .
Repair or replace the connector.

STEP 3. Perform voltage measurement at B-09 engine-ECU connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 92 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 5 .
Go to Step 4 .

STEP 4. Connector check: C-304 ETACS-ECU connector


Q. Is the check result normal?

    Check and repair harness between C-304 (terminal No. 10) ETACS-ECU connector and B-09 (terminal No. 92) engine-ECU connector.

    • Check signal line for open/short circuit.
Repair or replace the connector.

STEP 5. Connector check: C-304 ETACS-ECU connector

Q. Is the check result normal?
Go to Step 6 .
Repair or replace the connector.

STEP 6. Check harness between C-304 (terminal No. 10) ETACS-ECU connector and B-09 (terminal No. 92) engine-ECU connector.

  • Check signal line for damage.

Q. Is the check result normal?
Go to Step 7 .
Repair the damaged harness wire.

STEP 7. Connector check: A-33X engine control relay connector

Q. Is the check result normal?
Go to Step 8 .
Repair or replace the connector.

STEP 8. Check engine control relay itself.

  • Check engine control relay itself (Refer to ).

Q. Is the check result normal?
Go to Step 9 .
Replace the engine control relay.

STEP 9. Check harness between A-33X (terminal No. 1) engine control relay connector and B-09 (terminal No. 73) engine-ECU connector.

  • Check signal line for short circuit.

Q. Is the check result normal?
Go to Step 10 .
Repair the damaged harness wire.

STEP 10. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

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