Code No. P0090: Fuel Pressure Control Solenoid Valve System

OPERATION

Power is supplied from the engine control relay (terminal No. 4) to the fuel pressure control solenoid valve (terminal No. 1).
The engine-ECU controls the fuel pressure control solenoid valve by turning the power transistor in the engine-ECU.

FUNCTION

In response to a signal from the engine-ECU, the fuel pressure control solenoid valve switches the pressure to be introduced into the fuel pressure regulator between the intake manifold negative pressure and atmospheric pressure.

TROUBLE JUDGMENT

Check Condition

Battery voltage is 10 V or more.

Judgment Criterion

Surge voltage cannot be detected within 1 seconds from the time when the fuel pressure control solenoid valve has changed from ON to OFF.

PROBABLE CAUSE

Failed fuel pressure control solenoid valve
Open/short circuit and damage in fuel pressure control solenoid valve circuit or loose connector contact
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III actuator test

Item No. 11: Fuel pressure control solenoid valve

OK: Operating sound can be heard and the valve vibrates.

Q. Is the check result normal?

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

	Go to Step 2 .

STEP 2. Connector check: A-144 fuel pressure control solenoid valve connector

Q. Is the check result normal?

Go to Step 3 .

Repair or replace.

STEP 3. Perform resistance measurement at A-144 fuel pressure control solenoid valve connector.

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

OK: 29 - 35 Ω (at 20°C)

Q. Is the check result normal?

Go to Step 4 .

Replace fuel pressure control solenoid valve.

STEP 4. Perform voltage measurement at A-144 fuel pressure control solenoid 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 6 .

Go to Step 5 .

STEP 5. Connector check: B-206 engine control relay connector

Q. Is the check result normal?

Check power supply line for open/short circuit.

Repair or replace.

STEP 6. Perform voltage measurement at A-34 engine-ECU connector.

Disconnect engine-ECU connector and connect special tool power plant ECU check harness (MB991987), and then measure the voltage on the check connector.
Ignition switch: "ON"
Voltage between terminal No. 66 and earth.

OK: System voltage

Q. Is the check result normal?

Go to Step 8 .

Go to Step 7 .

STEP 7. Connector check: A-34 engine-ECU connector

Q. Is the check result normal?

Check output line for open/short circuit.

Repair or replace.

STEP 8. Connector check: A-34 engine-ECU connector

Q. Is the check result normal?

Go to Step 9 .

Repair or replace.

STEP 9. Check harness between A-144 (terminal No. 2) fuel pressure control solenoid valve connector and A-34 (terminal No. 66) engine-ECU connector.

Check output line for damage.

Q. Is the check result normal?

Go to Step 10 .

Repair.

STEP 10. Check harness between A-144 (terminal No. 1) fuel pressure control solenoid valve connector and B-206 (terminal No. 4) engine control relay connector.

note

Before checking harness, check intermediate connector A-36 and B-212, 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 actuator test

Item No. 11: Fuel pressure control solenoid valve

OK: Operating sound can be heard and the valve vibrates.

Q. Is the check result normal?

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

	Replace engine-ECU then perform the variamt coding (Refer to GROUP 00 - Precautions Before Service -How to Perform Variant Coding ).