P0551
DTC P0551: Power Steering Pressure Sensor Circuit Range/PerformancePower Steering Pressure Sensor Circuit Part 1:
Power Steering Pressure Sensor Circuit Part 2:
CIRCUIT OPERATION
A 5-volt voltage is supplied to the power steering pressure sensor power terminal (terminal No. 3) from the ECM (terminal No. 43).
The ground terminal (terminal No. 1) is grounded with the ECM (terminal No. 59).
A voltage that is proportional to the power steering pressure is sent to the ECM (terminal No. 58) from the power steering pressure sensor output terminal (terminal No. 2).
TECHNICAL DESCRIPTION
The power steering pressure sensor outputs a voltage which corresponds to the power steering pressure.
The ECM checks whether this voltage is within a specified range.
DESCRIPTIONS OF MONITOR METHODS
Power steering pressure sensor output stays high during specified go/stop operations.
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:
Logic Flow Chart
Check Conditions
Engine coolant temperature is higher than 7 °C (45 °F).
Drive for 4 seconds or more with the vehicle speed is 50 km/h (31 mph) or more. Stop the vehicle [vehicle speed is 1.5 km/h (1.0 mph) or less]. Repeat 10 times or more.
Judgement Criterion
Power steering pressure is continues to be 2.0 MPa (290 psi) or higher.
OBD-II DRIVE CYCLE PATTERN None.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
Connector damage.
Harness damage.
Power steering pressure sensor failed.
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 24: Power Steering Pressure sensor.
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 item24, Power Steering Pressure sensor.
- If the steering wheel is not turned while idling, voltage should be between 400 and 1,000 mV.
- If the steering wheel is turned while idling, voltage should be between 3,000 and 4,000 mV.
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.
NO: Go to Step 2.
STEP 2. Check harness connector B-102 at power steering pressure switch and harness connector B-10 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 3.
NO: Repair or replace it. Then go to Step 6.
STEP 3. Check for open circuit and harness damage between power steering pressure sensor connector B-102 and ECM connector B-10.
1. Disconnect the connector B-102 and B-10 measure at the harness side.
2. Measure the resistance between B-102 connector and B-10 connector.
a. Connector B-102 (terminal No. 1) and connector B-10 (terminal No. 59).
b. Connector B-102 (terminal No. 2) and connector B-10 (terminal No. 58).
c. Connector B-102 (terminal No. 3) and connector B-10 (terminal No. 43).
- Should be less than 2 ohms.
Q: Is the measured resistance less than 2 ohms?
YES: Then go to Step 4.
NO: Repair it. Then go to Step 6.
STEP 4. Check for short circuit to ground between power steering pressure sensor connector B-102 and ECM connector B-10.
1. Disconnect the connector B-102 and B-10 measure at the harness side.
2. Check for the continuity between B-102 connector and ground.
a. Connector B-102 (terminal No. 1) and ground.
b. Connector B-102 (terminal No. 2) and ground.
c. Connector B-102 (terminal No. 3) and ground.
- Not continuity.
Q: Is the harness wire in good condition?
YES: Then go to Step 5.
NO: Repair it. Then go to Step 6.
STEP 5. Replace the power steering pressure sensor.
1. Replace the power steering pressure sensor.
2. Check data list.
3. Start the engine and run at idle.
4. Set scan tool MB991958 to the data reading mode for item 24, Power Steering Pressure sensor.
- If the steering wheel is not turned while idling, voltage should be between 400 and 1,000 mV.
- If the steering wheel is turned while idling, voltage should be between 3,000 and 4,000 mV.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: The inspection is complete.
NO: Replace the ECM. When the ECM is replaced, register the ID code. Refer to ID Code Registration Judgment Table
STEP 6. Using scan tool MB991958, check data list item 24: Power Steering Pressure sensor.
1. Start the engine and run at idle.
2. Set scan tool MB991958 to the data reading mode for item 24, Power Steering Pressure sensor.
- If the steering wheel is not turned while idling, voltage should be between 400 and 1,000 mV.
- If the steering wheel is turned while idling, voltage should be between 3,000 and 4,000 mV.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: The inspection is complete.
NO: Retry the troubleshooting.