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. 127)

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 .

  1. 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. 127) engine-ECU connector and A-134 (terminal No. 1) power steering fluid pressure switch connector.


note Before checking harness, check intermediate connectors 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 - Precautions Before Service - 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 ). After registering the injector identification code, the vehicle equipped with the DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Emission Control - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).

Repair the damaged harness wire.

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

  • Refer to Data List Reference Table .

  1. 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 is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - 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 ). After registering the injector identification code, the vehicle equipped with the DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Emission Control - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).