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DTC P0452: Evaporative Emission Control System Pressure Sensor Low Input
 
 
 
 
CIRCUIT OPERATION
  • The ECM terminal FPR5 supplies a 5 volts reference signal to the fuel tank differential pressure sensor. The fuel tank differential pressure sensor is grounded through the ECM terminal FPRE.
  • The fuel tank differential pressure sensor returns a voltage signal to the ECM terminal F/PR 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
  • Fuel tank differential pressure sensor output voltage is out of specified range.
 
 
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
  • Fuel temperature sensor monitor
  • Fuel level sensor 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)
 
 
Check Condition
  • 2 seconds or more have passed since the starting sequence was completed.
Judgment Criterion
  • The fuel tank differential pressure sensor output voltage remains 0.2 volt or less for 5 seconds.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • None
 
 
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23 .
 
 
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE: )
  • Fuel tank differential pressure sensor failed.
  • Open or shorted fuel tank differential pressure sensor circuit, connector damage.
  • ECM failed.
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle Communication Interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite Main Harness A
  • MB992747: V.C.I.-Lite USB Cable Short
  • MB992748: V.C.I.-Lite USB Cable Long
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)
    • MB991824: Vehicles Communication Interface (V.C.I.)
    • MB991827: M.U.T.-III USB Cable
    • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
  • MB992110: Power Plant ECU Check Harness
STEP 1. Using scan tool (M.U.T.-III), check data list item 52: Fuel Tank Differential Pressure Sensor.
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
(1) Connect scan tool (M.U.T-III). Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) .
(2) Disconnect the hose D from the evaporative emission canister.
(3) Plug the disconnected end of hose D.
(4) Turn the ignition switch to the "ON" position.
(5) Remove the fuel cap.
(6) Set scan tool (M.U.T.-III) to the data reading mode for item 52, Fuel Tank Differential Pressure Sensor.
  • Output voltage should be between 1,500 to 3,500 mV.
(7) 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.
(8) Turn the ignition switch to the "LOCK" (OFF) position.
(9) Remove the evaporative emission system pressure pump (Miller number 6872A) and the fuel tank adapter (MLR-8382), and reinstall the fuel cap.
(10) Connect hose D to the evaporative emission canister.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting / Inspection Service Points - How to Cope with Intermittent Malfunctions .
Go to Step 2 .
 
STEP 2. Measure the sensor supply voltage at fuel tank differential pressure sensor connector by backprobing.
(1) Do not disconnect the fuel tank differential pressure sensor connector.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal FPR5 line and ground by backprobing.
  • Voltage should be between 4.9 and 5.1 volts.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the measured voltage between 4.9 and 5.1 volts?
Go to Step 5.
Go to Step 3.
 
STEP 3. Measure the sensor supply voltage at ECM connector by using power plant ECU 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) Measure the voltage between terminal FPR5 and ground.
  • Voltage should be between 4.9 and 5.1 volts.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the measured voltage between 4.9 and 5.1 volts?
Repair or replace the connector(s), or check and repair the harness of open circuit in FPR5 line between fuel tank differential pressure sensor connector and ECM connector. Then go to Step 8.
Go to Step 4.
 
STEP 4. Check of short circuit to ground in FPR5 line between fuel tank differential pressure sensor connector and ECM connector.
Is the harness wire in good condition?
Go to Step 7.
Repair it. Then go to Step 8.
 
STEP 5. Measure the sensor output voltage at ECM connector by using power plant ECU 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 F/PR and ground.
  • Voltage should be between 1.5 and 3.5 volts.
(5) Turn the ignition switch to the "LOCK" (OFF) position.
Is the measured voltage normal?
Go to Step 7.
Go to Step 6.
 
STEP 6. Check of short to ground and open circuit in F/PR line between fuel tank differential pressure sensor connector and ECM connector.
Is the harness wire in good condition?
Replace the fuel tank differential pressure sensor. Then go to Step 8.
Repair it. Then go to Step 8.
 
STEP 7. Using scan tool (M.U.T.-III), check data list item 52: Fuel Tank Differential Pressure Sensor.
(1) Disconnect hose D from the evaporative emission canister.
(2) Plug the disconnected end of hose D.
(3) Turn the ignition switch to the "ON" position.
(4) Remove the fuel cap.
(5) Set scan tool (M.U.T.-III) to the data reading mode for item 52, Fuel Tank Differential Pressure Sensor.
  • Output voltage should be between 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.
(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.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting / Inspection Service Points - How to Cope with Intermittent Malfunctions .
Replace the ECM (Refer to Removal and Installation ). Then go to Step 8.
 
STEP 8. Perform 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 23 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P0452 stored?
Repeat the troubleshooting.
The procedure is complete.