Inspection Procedure 29: 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 .

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.