Code No. P0551: Power Steering Fluid Pressure Switch System

OPERATION

The battery voltage is applied to the power steering pressure switch (terminal No. 1) from the engine-ECU (terminal No. 96)

FUNCTION

It is detected whether a load is applied on the power steering fluid pump by steering or not, and the signal is inputted to the engine-ECU. When the power steering fluid pressure switch "ON" signal (a large load on the power steering fluid pump) is inputted, the engine-ECU provides the idle-up control.

TROUBLE JUDGMENT

Check Condition

Within 5 seconds after the ignition switch is in the "OFF" position.

Judgment Criterion

For 2 seconds, the power steering fluid pressure switch is in the "ON" position and the engine continuously stops.

PROBABLE CAUSES

Failed power steering fluid pressure switch
Short circuit in power steering fluid pressure switch circuit or loose connector contact
Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list.

Refer to Data List Reference Table .

Item 75: Power steering fluid pressure switch

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-134 power steering pressure switch connector

Q. Is the check result normal?

Go to Step 3 .

Repair or replace the connector.

STEP 3. Check power steering pressure switch itself.

Disconnect A-134 power steering fluid pressure switch connector.
Continuity between terminal No.1 and earth.

OK: No continuity

Q. Is the check result normal?

	Replace the power steering fluid pressure switch.

	Go to Step 4 .

STEP 4. Check at A-134 power steering fluid pressure switch 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 7 .

Go to Step 5 .

STEP 5. Connector check: C-103 engine-ECU connector

Q. Is the check result normal?

Go to Step 6 .

Repair or replace the connector.

STEP 6. Check harness between C-103 (terminal No. 96) engine-ECU connector and A-134 (terminal No. 1) power steering fluid pressure switch connector.

note

Before checking harness, check intermediate connector A-27 and A-115, and repair if necessary.

Check output line for short circuit.

Q. Is the check result normal?

Replace the engine-ECU. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - How to Perform Chassis Number Writing

). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns

Repair the damaged harness wire.

STEP 7. M.U.T.-III data list.

Refer to Data List Reference Table .

Item 75: Power steering fluid pressure switch

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 the engine-ECU. When the engine-ECU replaced, write the chassis number (Refer to GROUP 00 - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).