Inspection Procedure 24: Power steering fluid pressure switch system








OPERATION



  • 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.

PROBABLE CAUSES



  • Failed power steering fluid pressure switch
  • Damaged harness (Open or short circuit between power steering fluid pressure switch and engine-ECU)
  • Damaged connector (Engine-ECU connector, power steering fluid pressure switch connector)
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-21 power steering fluid pressure switch connector

Q. Is the check result normal?
Go to Step 2 .
Repair or replace.

STEP 2. 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 8 .
Go to Step 3 .

STEP 3. Perform voltage measurement at D-215 engine-ECU connector.

  • Measure engine-ECU terminal voltage.
  • Ignition switch: ON
  • Voltage between terminal No. 127 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 4 .
Go to Step 5 .

STEP 4. Connector check: D-215 engine-ECU connector

Q. Is the check result normal?

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

    • Check output line for open circuit.
Repair or replace.

STEP 5. Connector check: D-215 engine-ECU connector


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

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

  • Check output line for short circuit.

Q. Is the check result normal?
Go to Step 7 .
Repair the 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 ).

STEP 8. Perform voltage measurement at D-215 engine-ECU connector.

  • Measure engine-ECU terminal voltage.
  • Engine: Idling
  • Voltage between terminal No. 127 and earth.
OK:
    System voltage (Steering wheel: Stationary)
    1 V or less (Steering wheel: Turned)

Q. Is the check result normal?
Go to Step 11 .
Go to Step 9 .

STEP 9. Connector check: D-215 engine-ECU connector

Q. Is the check result normal?
Go to Step 10 .
Repair or replace.

STEP 10. Check harness between B-21 (terminal No. 1) power steering fluid pressure switch connector and D-215 (terminal No. 127) engine-ECU connector.

  • Check output line for damage.

Q. Is the check result normal?
Replace the power steering fluid pressure switch.
Repair the harness wire.

STEP 11. Connector check: D-215 engine-ECU connector

Q. Is the check result normal?
Go to Step 7 .
Repair or replace.