P0452
DTC P0452: Evaporative Emission System Pressure Sensor Low InputSystem diagram
System Diagram:
FUEL TANK DIFFERENTIAL PRESSURE SENSOR CIRCUIT
Fuel Tank Differential Pressure Sensor Circuit (Part 1):
Fuel Tank Differential Pressure Sensor Circuit (Part 2):
CIRCUIT OPERATION
- The ECM (terminal No. 114) supplies a 5 volts reference signal to the fuel tank differential pressure sensor (terminal No. 3). The fuel tank differential pressure sensor (terminal No. 2) is grounded through the ECM (terminal No. 113).
- The fuel tank differential pressure sensor (terminal No. 1) returns a voltage signal to the ECM (terminal No. 112) that is proportional to the pressure in the fuel tank.
TECHNICAL DESCRIPTION
- The ECM monitors the fuel tank differential pressure sensor output voltage.
- The ECM determines whether the fuel tank differential pressure sensor signal voltage is within normal operating parameters.
DESCRIPTIONS OF MONITOR METHODS
- Compare purge solenoid status with fuel tank differential pressure sensor output voltage.
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)
- Evaporative emission purge solenoid monitor
- Evaporative emission ventilation solenoid monitor
Sensor (The sensors below are determined to be normal)
- Mass airflow sensor
- Barometric pressure sensor
- Intake air temperature sensor
- Engine coolant temperature sensor
- Accelerator pedal position sensor
DTC SET CONDITIONS
Logic Flow Chart (Monitor Sequence)
Logic Flow Chart (Monitor Sequence):
Check Conditions
- 2 seconds or more have passed since the starting sequence was completed.
Judgement Criteria
- The fuel tank differential pressure sensor output voltage remains 0.2 volt or less for 5 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to MFI, Diagnostic Function - OBD-II Drive Cycle - Pattern 24. OBD-II Drive Cycle
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE:)
- Connector damage.
- Harness damage.
- Fuel tank differential pressure sensor failed.
- ECM failed.
OVERVIEW OF TROUBLESHOOTING
- DTC P0452 can be set by a faulty fuel tank differential pressure sensor or related circuit, or ECM failure.
- To check for system blockage, do a performance test which uses a mechanical vacuum gauge and scan tool MB991958 set on the fuel tank differential pressure sensor (52: Fuel tank differential PRS SNSR). The mechanical gauge reading is used to verify scan tool MB991958 reading. A comparison of the mechanical gauge with the reading on scan tool MB991958 will locate a problem in the system.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A
- MB992110: Power Plant ECU Check Harness
STEP 1. Using scan tool MB991958, check data list item 52: Fuel Tank Differential 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. Disconnect hose D from the evaporative emission canister, and plug the hose.
3. Turn the ignition switch to the "ON" position.
4. Remove the fuel cap.
5. Set scan tool MB991958 to the data reading mode.
- Item 52, Fuel Tank Differential Pressure Sensor.
- The fuel tank pressure reading on the scan tool should be 1,500 to 3,500 mV.
6. Connect the evaporative emission system pressure pump (Miller number 6872A) to the fuel tank filler tube by using fuel tank adapter (MLR-8382) and pressurize the fuel tank.
- The fuel tank pressure reading should increase.
7. Turn the ignition switch to the "LOCK" (OFF) position. Then disconnect scan tool MB991958.
8. Remove the evaporative emission system pressure pump (Miller number 6872A) and the fuel tank adapter (MLR-8382), and reinstall the fuel cap.
9. Connect hose D to the evaporative emission canister.
Q: Does the output voltage of differential pressure sensor increase when pressure the fuel tank?
YES : It can be assumed that this malfunction is intermittent (Refer to General (Body and Chassis), How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
NO : Go to Step 2.
STEP 2. Check harness connector B-109 at ECM and harness connector D-17 at fuel tank differential pressure sensor for damage.
Q: Is the harness connector in good condition?
YES : Then go to Step 3.
NO : Repair or replace it. Refer to General (Electrical), Harness Connector Inspection. Then go to Step 8.
STEP 3. Measure the 5 volts reference signal at fuel tank differential pressure sensor connector D-17.
1. Remove the rear seat assembly (Refer to Interior, Rear Seat Assembly Removal And Installation).
2. Remove the floor inspection lid (LH).
3. Disconnect fuel tank differential pressure sensor connector D-17.
4. Turn the ignition switch to the "ON" position.
5. Measure the voltage between terminal 3 and ground.
- The voltage should measure between 4.9 and 5.1 volts.
6. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.9 and 5.1 volts?
YES : Go to Step 6.
NO : Go to Step 4.
STEP 4. Measure the 5 volts reference signal at ECM connector B-109 by using check harness special tool MB992110.
1. Disconnect all ECM connectors. Connect the power plant ECU check harness special tool MB992110 between the separated connectors.
2. Turn the ignition switch to the "ON" position.
3. Remove the fuel cap.
4. Measure the voltage between terminal 114 and ground.
- The voltage should measure between 4.9 and 5.1 volts.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.9 and 5.1 volts?
YES : Check harness connector C-39 at intermediate connector for damage, and repair or replace as required. Refer to General (Electrical), Harness connector Inspection. If intermediate connector C-39 is in good condition, repair it because of harness damage fuel tank differential pressure sensor connector D-17 (terminal No. 3) and ECM connector B-109 (terminal No. 114). Then go to Step 8.
NO : Go to Step 5.
STEP 5. Check for short circuit to ground between fuel tank differential pressure sensor connector D-17 and ECM connector B-109.
1. Disconnect the connector D-17 and B-109 measure at the harness side.
2. Check for the continuity between connector B-109 (terminal No. 114) and ground.
- No continuity.
Q: Is the harness wire in good condition?
YES : Replace the ECM. When the ECM is replaced, register the ID code. Refer to ID Code Registration Judgment Table
NO : Check harness connector C-39 at intermediate connector for damage, and repair or replace as required. Refer to General (Electrical), Harness connector Inspection. If intermediate connector C-39 is in good condition, repair it because of short circuit to fuel tank differential pressure sensor connector D-17 (terminal No. 3) and ECM connector B-109 (terminal No. 114). Then go to Step 8.
STEP 6. Check for open circuit or short circuit to ground or harness damage between fuel tank differential pressure sensor connector D-17 and ECM connector B-109.
1. Disconnect the connector D-17 and B-109 measure at the harness side.
a. Measure the resistance between connector D-17 (terminal No. 1) and connector B-109 (terminal No. 112).
b. Measure the resistance between connector D-17 (terminal No. 2) and connector B-109 (terminal No. 113).
- Should be less than 2 ohms.
a. Check for the continuity between connector B-109 (terminal No. 112) and ground.
b. Check for the continuity between connector B-109 (terminal No. 113) and ground.
- No continuity.
Q: Is the harness connector in good condition?
YES : Then go to Step 7.
NO : Repair it. Then go to Step 8.
STEP 7. Replace the fuel tank differential pressure sensor.
1. Replace the fuel tank differential pressure sensor.
2. Carry out test drive with the drive cycle pattern. Refer to MFI, Diagnostic Function - OBD-II Drive Cycle - Pattern 23. OBD-II Drive Cycle
3. Check the diagnostic trouble code (DTC).
Q: Is DTC P0452 set?
YES : Replace the ECM. When the ECM is replaced, register the ID code. Refer to ID Code Registration Judgment Table
NO : The inspection is complete.
STEP 8. Perform the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to MFI, Diagnostic Function - OBD-II Drive Cycle - Pattern 23. OBD-II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0452 set?
YES : Repeat the troubleshooting.
NO : The procedure is complete.