Code No. P0551: Power Steering Fluid Pressure Switch System








OPERATION



  • The battery voltage is applied to the power steering fluid 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: B-21 power steering fluid pressure switch connector

Q. Is the check result normal?
Go to Step 3
Repair or replace the connector.

STEP 3. Check power steering fluid pressure switch itself.

  • Disconnect B-21 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. Perform voltage measurement at B-21 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: D-215 engine-ECU connector

Q. Is the check result normal?
Go to Step 6.
Repair or replace the connector.

STEP 6. Check harness between D-215 (terminal No. 127) engine-ECU connector and B-21 (terminal No. 1) power steering fluid pressure switch connector.

  • 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 closed type DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - 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 closed type DPF carries out the forcible DPF regeneration. (Refer to GROUP 17 - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ).