Inspection Procedure 26: 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. 96 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. 96) 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. 96) 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 .

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 - 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 ).

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

Measure engine-ECU terminal voltage.
Engine: Idling
Voltage between terminal No. 96 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. 96) 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.