Inspection Procedure 1: Communication with Engine-ECU <M/T> or Engine-A/T-ECU <A/T> is Not Possible.

OPERATION

There is data communication between diagnosis connector output terminal (terminal No. 7) and engine-ECU <M/T>or engine-A/T-ECU (terminal No. 74).

COMMENT ON TROUBLE SYMPTOM

The failure possibly occurs when engine-ECU <M/T> or engine-A/T-ECU <A/T> detects malfunction, or is caused by malfunction of open/short in the diagnosis connector circuit.

PROBABLE CAUSE

Open/short circuit in engine-ECU <M/T> or engine-A/T-ECU <A/T> power circuit
Between engine-ECU <M/T> or engine-A/T-ECU <A/T> and diagnosis connector for short circuit
Failed engine-ECU <M/T>
Failed engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. Check engine starting.

Q. Is engine starting possible?

	Go to Step 2 .

	Check engine-ECU <M/T> or engine-A/T-ECU <A/T> power supply, engine control relay and ignition switch- IG1 system (Refer to Inspection Procedure 22 ).

STEP 2. Connector check: C-112 engine-ECU <M/T> connector or engine-A/T-ECU <A/T> connector

Q. Is the check result normal?

Go to Step 3 .

Repair or replace.

STEP 3. Check harness between C-126 (terminal No. 7) diagnosis connector and C-112 (terminal No. 74) engine-ECU <M/T> connector or engine-A/T-ECU <A/T> connector.

note

Before checking harness, check intermediate connectors C-17 and repair if necessary.

Check communication line for open/short circuit and damage.

Q. Is the check result normal?

Go to Step 4 .

Repair.

STEP 4: Check the trouble symptom.

Q. Does trouble symptom persist?

	Replace engine-ECU <M/T> or engine-A/T-ECU <A/T>.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).