Code No. P0606: Engine-ECU Main Processor Malfunction

OPERATION

Refer to Inspection Procedure 19: Engine-ECU Power Supply, Engine Control Relay, Ignition Switch-IG1 System .

FUNCTION

System LSI checks the engine-ECU for abnormal conditions.

TROUBLE JUDGMENT

Check Condition

Ignition switch is "ON" position.

Judgement Criterion

No surveillance pulse signals should be input.

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-30 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-30 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-30 (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-30 (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-30 (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 the 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 ).