P0554

DTC P0554: Power Steering Pressure Switch Circuit Intermittent

Power Steering Pressure Switch Circuit:

CIRCUIT OPERATION
- A battery positive voltage is applied to the power steering pressure switch output terminal (terminal No. 1) from the ECM (terminal No. 37) 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 volt 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)
- Not applicable

Sensor (The sensor below is determined to be normal)
- Engine coolant temperature sensor

DTC SET CONDITIONS

Logic Flow Chart:

LOGIC FLOW CHART

Check Conditions
- Engine coolant temperature is higher than 30 °C (86 °F).
- Vehicle speed is higher than 50 km/h (31 mph).

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

OBD-II DRIVE CYCLE PATTERN
None.

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 (MUT-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B




STEP 1. Using scan tool MB991958, check data list item 27: 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 27, Power Steering Pressure Switch.
- If the steering wheel is stopped while idling, "OFF" will be displayed.
- If the steering wheel is steered 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. Refer to How to Use Troubleshooting/Inspection Service Points.

NO: Go to Step 2.

STEP 2. Check the power steering fluid level.
Refer to On-Vehicle Service - Fluid Level Check.

Q: Are there any abnormalities?

YES: Go to Step 3.

NO: Repair it. Then go to Step 7.

STEP 3. Check the power steering pressure switch.
Refer to On-Vehicle Service - Power Steering Pressure Switch Check.

Q: Are there any abnormalities?

YES: Go to Step 4.

NO: Replace the power steering pressure switch. Then go to Step 7.

STEP 4. Check the oil pump pressure.
Refer to On-Vehicle Service - Oil Pump Pressure Test.

Q: Are there any abnormalities?

YES: Go to Step 5.

NO: Repair it. Then go to Step 7.







STEP 5. Check harness connector A-40 at the power steering pressure switch and connector C-119 at ECM for damage.

Q: Is the harness connector in good condition?

YES: Go to Step 6.

NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 7.







STEP 6. Check for harness damage between power steering pressure switch connector A-40 (terminal No. 1) and ECM connector C-119 (terminal No. 37).

NOTE: Check harness after checking intermediate connector A-13. If intermediate connector is damaged, repair or replace it. Refer to Harness Connector Inspection. Then go to Step 7.

Q: Is the harness wire in good condition?

YES: Replace the ECM. Then go to Step 7.

NO: Repair it. Then go to Step 7.




STEP 7. Using scan tool MB991958, check data list item 27: 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 27, 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 switch operating properly?

YES: The procedure is complete.

NO: Repeat the troubleshooting.