Inspection Procedure 28: Power steering fluid pressure switch system








CONDITION



  • The battery voltage is applied to the power steering fluid pressure switch (terminal No. 1) from the engine-ECU <M/T> or engine-A/T-ECU <A/T> (terminal No. 47).

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 <M/T> or engine-A/T-ECU <A/T>. When the power steering fluid pressure switch "ON" signal (a large load on the power steering fluid pump) is inputted, the engine-ECU <M/T> or engine-A/T-ECU <A/T> provides the idle-up control.

PROBABLE CAUSES



  • Failed power steering fluid pressure switch
  • Open/short circuit in power steering fluid pressure switch circuit or loose connector contact
  • Failed engine-ECU <M/T>
  • Failed engine-A/T-ECU <A/T>

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 the connector.

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-244 engine-ECU <M/T> connector or D-214 engine-A/T-ECU <A/T> connector.

  • Measure engine-ECU <M/T> or engine-A/T-ECU <A/T> terminal voltage.
  • Ignition switch: ON
  • Voltage between terminal No. 47 and earth.
OK: System voltage

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

STEP 4. Connector check: D-244 engine-ECU <M/T> connector or D-214 engine-A/T-ECU <A/T> 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-244 (terminal No. 47) engine-ECU <M/T> connector or D-214 (terminal No. 47) engine-A/T-ECU <A/T> connector.

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

STEP 5. Connector check: D-244 engine-ECU <M/T> connector or D-214 engine-A/T-ECU <A/T> connector


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

STEP 6. Check harness between B-21 (terminal No. 1) power steering fluid pressure switch connector and D-244 (terminal No. 47) engine-ECU <M/T> connector or D-214 (terminal No. 47) engine-A/T-ECU <A/T> connector.

  • Check output line for short circuit.

Q. Is the check result normal?
Go to Step 7 .
Repair the damaged harness wire.

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

  • Refer to Data List Reference Table .

  1. Item 83: 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 <M/T> or engine-A/T-ECU <A/T>.

STEP 8. Perform voltage measurement at D-244 engine-ECU <M/T> connector or D-214 engine-A/T-ECU <A/T> connector.

  • Measure engine-ECU <M/T> or engine-A/T-ECU <A/T> terminal voltage.
  • Engine: Idling
  • Voltage between terminal No. 47 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-244 engine-ECU <M/T> connector or D-214 engine-A/T-ECU <A/T> connector

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

STEP 10. Check harness between B-21 (terminal No. 1) power steering fluid pressure switch connector and D-244 (terminal No. 47) engine-ECU <M/T> connector or D-214 (terminal No. 47) engine-A/T-ECU <A/T> connector.

  • Check output line for damage.

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

STEP 11. Connector check: D-244 engine-ECU <M/T> connector or D-214 engine-A/T-ECU <A/T> connector

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