Code No. P0075: Oil Control Valve Circuit

OPERATION

Power is supplied to the oil control valve (terminal No. 1) from the engine control relay (terminal No. 1).
The engine-ECU <M/T> or engine-A/T-ECU <A/T> (terminal No. 95) makes the power transistor in the unit be in ON position, and that makes currents go on the oil control valve (terminal No. 2).

FUNCTION

The oil control valve switches the cams to operate the MIVEC in the low-speed or high-speed mode in accordance with the signals from the engine-ECU <M/T> or engine-A/T-ECU <A/T>.

TROUBLE JUDGMENT

Check Condition

The oil control valve does not operate. (i.e. when the ignition switch is in ON position or the engine runs at the idle speed and so on)

Judgment Criterion

The oil control valve drive terminal voltage of the engine-ECU <M/T> or engine-A/T-ECU <A/T> is not normal for 2 seconds or more.

PROBABLE CAUSE

Failed purge oil control valve
Open/short circuit in oil control valve circuit or loose connector contact
Failed engine-ECU <M/T>
Failed engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-07 oil control valve connector

Q. Is the check result normal?

Go to Step 2 .

Repair or replace.

STEP 2: Perform resistance measurement at B-07 oil control valve connector.

Disconnect connector, and measure at control valve side.
Resistance between terminal No. 1 and No. 2.

OK: 6.9 - 7.9 Ω (at 20°C)

Q. Is the check result normal?

Go to Step 3 .

Replace oil control valve.

STEP 3. Perform voltage measurement at B-07 oil control valve connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal No. 1 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 5 .

Go to Step 4 .

STEP 4. Connector check: B-15X engine control relay connector

Q. Is the check result normal?

Check power line for open/short circuit.

Repair or replace.

STEP 5. Perform voltage measurement at C-113 engine-ECU <M/T> connector or engine-A/T-ECU <A/T> connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal No. 95 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 7 .

Go to Step 6 .

STEP 6. Connector check: C-113 engine-ECU <M/T> connector or engine-A/T-ECU <A/T> connector

Q. Is the check result normal?

Check output line for open/short circuit.

Repair or replace.

STEP 7. Connector check: C-113 engine-ECU <M/T> connector or engine-A/T-ECU <A/T> connector

Q. Is the check result normal?

Go to Step 8 .

Repair or replace.

STEP 8. Check harness between B-07 (terminal No. 2) oil control valve connector and C-113 (terminal No. 95) engine-ECU <M/T> connector or engine-A/T-ECU <A/T> connector.

Check output line for damage.

Q. Is the check result normal?

Go to Step 9 .

Repair.

STEP 9. Connector check: B-15X engine control relay connector.

Q. Is the check result normal?

Go to Step 10 .

Repair or replace.

STEP 10. Check harness between B-07 (terminal No. 1) oil control valve connector and B-15X (terminal No. 1) engine control relay connector.

note

Before checking harness, check intermediate connector C-116, and repair if necessary.

Check power supply line for damage.

Q. Is the check result normal?

Go to Step 11 .

Repair.

STEP 11. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?

	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 ).