Code No. P0551: Power Steering Fluid Pressure Switch System <Vehicles for Hong kong>

CONDITION

The battery voltage is applied to the power steering fluid pressure switch (terminal No. 1) from the engine-A/T-ECU (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-A/T-ECU. When the power steering fluid pressure switch "ON" signal (a large load on the power steering fluid pump) is inputted, the engine-A/T-ECU provides the idle-up control.

TROUBLE JUDGMENT

Check Conditions

Engine coolant temperature is 30°C or higher.

Drive the vehicle of 50 km/h or more for 4 seconds or more. Stop the vehicle (of 1.5 km/h or less). Repeat 10 times or more.

Judgment Criterion

Power steering pressure switch continues to be in "ON".

PROBABLE CAUSE

Failed power steering fluid pressure switch

Open/short circuit in power steering fluid pressure switch circuit or loose connector contact

Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-28 power steering fluid pressure switch connector

Q: Is the check result normal?

YES: Go to Step 2

.
NO: Repair.

STEP 2. Perform voltage measurement at B-28 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?

YES: Go to Step 8

.
NO: Go to Step 3

STEP 3. Perform voltage measurement at C-135 engine-A/T-ECU connector.

Measure engine-A/T-ECU terminal voltage.

Ignition switch: ON

Voltage between terminal No. 47 and earth.

OK: System voltage

Q: Is the check result normal?

YES: Go to Step 4

.
NO: Go to Step 5

STEP 4. Connector check: C-135 engine-A/T-ECU connector

Q: Is the check result normal?

YES:

Check and repair harness between B-28 (terminal No. 1) power steering fluid pressure switch connector and C-135 (terminal No. 47) engine-A/T-ECU connector.

Check output line for open circuit.

NO: Repair.

STEP 5. Connector check: C-135 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 6

.
NO: Repair.

STEP 6. Check harness between B-28 (terminal No. 1) power steering fluid pressure switch connector and C-135 (terminal No. 47) engine-A/T-ECU connector.

Check output line for short circuit.

Q: Is the check result normal?

YES: Go to Step 7

.
NO: Repair.

STEP 7. MUT-II/III data List

Refer to Data list reference table .

Item 27: Power steering fluid pressure switch

Q: Is the check result normal?

YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points

).
NO: Replace engine-A/T-ECU.

STEP 8. Perform voltage measurement at C-135 engine-A/T-ECU connector.

Measure engine-A/T-ECU 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?

YES: Go to Step 11

.
NO: Go to Step 9

STEP 9. Connector check: C-135 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 10

.
NO: Repair.

STEP 10. Check harness between B-28 (terminal No. 1) power steering fluid pressure switch connector and C-135 (terminal No. 47) engine-A/T-ECU connector.

Check output line for damage.

Q: Is the check result normal?

YES: Replace power steering fluid pressure switch.
NO: Repair.

STEP 11. Connector check: C-135 engine-A/T-ECU connector

Q: Is the check result normal?

YES: Go to Step 7

.
NO: Repair.


Code No. P0551: Power Steering Fluid Pressure Switch System <Vehicles for Hong kong>

CONDITION The battery voltage is applied to the power steering fluid pressure switch (terminal No. 1) from the engine-A/T-ECU (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-A/T-ECU. When the power steering fluid pressure switch "ON" signal (a large load on the power steering fluid pump) is inputted, the engine-A/T-ECU provides the idle-up control.
TROUBLE JUDGMENT Check Conditions Engine coolant temperature is 30°C or higher. Drive the vehicle of 50 km/h or more for 4 seconds or more. Stop the vehicle (of 1.5 km/h or less). Repeat 10 times or more. Judgment Criterion Power steering pressure switch continues to be in "ON".
PROBABLE CAUSE Failed power steering fluid pressure switch Open/short circuit in power steering fluid pressure switch circuit or loose connector contact Failed engine-A/T-ECU
	DIAGNOSIS PROCEDURE

	STEP 1. Connector check: B-28 power steering fluid pressure switch connector
	Q: Is the check result normal? YES: Go to Step 2 . NO: Repair.
	STEP 2. Perform voltage measurement at B-28 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? YES: Go to Step 8 . NO: Go to Step 3 .
	STEP 3. Perform voltage measurement at C-135 engine-A/T-ECU connector.
	Measure engine-A/T-ECU terminal voltage. Ignition switch: ON Voltage between terminal No. 47 and earth. OK: System voltage Q: Is the check result normal? YES: Go to Step 4 . NO: Go to Step 5 .
	STEP 4. Connector check: C-135 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Check and repair harness between B-28 (terminal No. 1) power steering fluid pressure switch connector and C-135 (terminal No. 47) engine-A/T-ECU connector. Check output line for open circuit. NO: Repair.
	STEP 5. Connector check: C-135 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 6 . NO: Repair.
	STEP 6. Check harness between B-28 (terminal No. 1) power steering fluid pressure switch connector and C-135 (terminal No. 47) engine-A/T-ECU connector.
	Check output line for short circuit. Q: Is the check result normal? YES: Go to Step 7 . NO: Repair.
	STEP 7. MUT-II/III data List Refer to Data list reference table . Item 27: Power steering fluid pressure switch Q: Is the check result normal? YES: Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points ). NO: Replace engine-A/T-ECU.
	STEP 8. Perform voltage measurement at C-135 engine-A/T-ECU connector.
	Measure engine-A/T-ECU 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? YES: Go to Step 11 . NO: Go to Step 9 .
	STEP 9. Connector check: C-135 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 10 . NO: Repair.
	STEP 10. Check harness between B-28 (terminal No. 1) power steering fluid pressure switch connector and C-135 (terminal No. 47) engine-A/T-ECU connector.
	Check output line for damage. Q: Is the check result normal? YES: Replace power steering fluid pressure switch. NO: Repair.
	STEP 11. Connector check: C-135 engine-A/T-ECU connector
	Q: Is the check result normal? YES: Go to Step 7 . NO: Repair.