P0554

DTC P0554: Power Steering Pressure Switch Circuit Intermittent














CIRCUIT OPERATION

- A battery positive voltage is applied to the power steering pressure switch output terminal (terminal No. 1) from the ECM (terminal No. 58) via the resistor in the ECM.

TECHNICAL DESCRIPTION

- The power steering pressure switch converts the existence of a power steering load into a high/low voltage, and inputs it into the ECM.
- When the steering wheel is turned, hydraulic pressure rises. The power steering pressure switch closes, and the applied battery positive voltage will be grounded. With this, the power steering pressure switch output voltage will fluctuate between 0 and 12 volts.
- While driving with the steering wheel held straight, the power steering pressure switch turns "OFF".
- The ECM checks whether the power steering pressure switch turns "OFF" or "ON" during driving.

DESCRIPTIONS OF MONITOR METHODS

Power steering pressure switch changes from off to on more than 10 times for 1 second.

MONITOR EXECUTION

Continuous

MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)

- Not applicable
Sensor (The sensor below is determined to be normal)

- Engine coolant temperature sensor

DTC SET CONDITIONS

Logic Flow Chart






Check Conditions

- Engine coolant temperature is higher than 65°C (149°F).
- Vehicle speed is 50 km/h (31 mph) or higher.
Judgement Criterion

- The ON/OFF frequency of a power steering pressure switch is 10 Hz or more for 20 seconds.

FAIL-SAFE AND BACKUP FUNCTION

- None

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 16 Monitors, Trips, Drive Cycles and Readiness Codes


TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)

- Power steering pressure switch failed.
- Incorrect power steering fluid level.
- Incorrect oil pump pressure.
- Harness damage in power steering pressure switch circuit, or connector damage.
- ECM failed.

DIAGNOSIS

Required Special Tools:

- MB991958: Scan tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A

STEP 1. Using scan tool MB991958, check data list item 83: Power Steering Pressure Switch.





CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK"
(OFF) position before connecting or disconnecting scan tool MB991958.

(1)Connect scan tool MB991958 to the data link connector.
(2)Start the engine and run at idle.
(3)Set scan tool MB991958 to the data reading mode for item 83, Power Steering Pressure Switch.

- If the steering wheel is not turned while idling, "OFF" will be displayed.
- If the steering wheel is turned while idling, "ON" will be displayed.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the sensor operating properly?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.

NO Go to Step 2.

STEP 2. Check the power steering fluid level.

Testing and Inspection.

Q. Are there any abnormalities?

YES Repair it. Then go to Step 7.
NO Go to Step 3.
STEP 3. Check the power steering pressure switch.

Testing and Inspection.

Q. Are there any abnormalities?

YES Replace the power steering pressure switch. Then go to Step 7.
NO Go to Step 4.
STEP 4. Check the oil pump pressure.

Oil Pump Pressure Test.

Q. Are there any abnormalities?

YES Repair it. Then go to Step 7.
NO Go to Step 5.
STEP 5. Check harness connector B-19 at the power steering pressure switch and harness connector B-09 at ECM for damage.

Q. Is the harness connector in good condition?

YES Go to Step 6.
NO Repair or replace it. Harness Connector Inspection.
Then go to Step 7.
STEP 6. Check for harness damage between power steering pressure switch connector B-19 (terminal No. 1) and ECM connector B-09 (terminal No. 58).

Q. Is the harness wire in good condition?

YES Replace the ECM (Refer to, Removal and Installation Removal and Replacement).
Then go to Step 7.
NO Repair it. Then go to Step 7.
STEP 7. Test the OBD-II drive cycle.

(1)Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 16 Monitors, Trips, Drive Cycles and Readiness Codes.

(2)Check the diagnostic trouble code (DTC).

Q. Is DTC P0554 set?

YES Retry the troubleshooting.
NO The inspection is complete.