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DTC P24D7: Fuel Tank Pressure Sensor Circuit Low Input
 
 
 
 
CIRCUIT OPERATION
  • The ECM terminal FPR5 supplies a 5 volts reference signal to the fuel tank pressure sensor. The fuel tank pressure sensor is grounded through the ECM terminal FPRE.
  • The fuel tank 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 pressure sensor output voltage.
  • The ECM determines whether the fuel tank pressure sensor signal voltage is within normal operating parameters.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • Fuel tank 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 set in memory for the item monitored below)
  • Not applicable
Sensor (The sensors below are determined to be normal)
  • Not applicable
 
 
DTC SET CONDITIONS
Logic Flow Chart (Monitor Sequence)
 
 
Check Condition
  • More than 2 seconds have passed since the power supply mode of electric motor switch was ON.
Judgment Criterion
  • Fuel tank pressure sensor output voltage is lower than 1.0 volt for 2 seconds.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • None
 
 
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .
 
 
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CODE TO BE SET ARE:)
  • Fuel tank pressure sensor failed.
  • Open or shorted fuel tank pressure sensor circuit, connector damage.
  • ECM failed.
 
 
DIAGNOSIS
Required Special Tool:
  • MB992110: Power Plant ECU Check Harness
STEP 1. Using scan tool (M.U.T.-IIISE), check data list item 211: Fuel Tank Pressure Sensor.
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
(1) Connect scan tool (M.U.T.-IIISE). Refer to HOW TO CONNECT THE SCAN TOOL (M.U.T.-IIISE) .
(2) Turn on the power supply mode of the electric motor switch.
(3) Remove the fuel cap.
(4) Set scan tool (M.U.T.-IIISE) to the data reading mode for item 211, Fuel Tank Pressure Sensor.
  • When altitude is 0 m (0 foot), 101 kPa (29.8 in.Hg).
  • When altitude is 600 m (1,969 feet), 95 kPa (28.1 in.Hg).
  • When altitude is 1,200 m (3,937 feet), 88 kPa (26.0 in.Hg).
  • When altitude is 1,800 m (5,906 feet), 81 kPa (23.9 in.Hg).
(5) Turn off the power supply mode of the electric motor switch.
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 pressure sensor connector.
(1) Disconnect the fuel tank pressure sensor connector and measure at the harness side.
(2) Turn on the power supply mode of the electric motor switch.
(3) Measure the voltage between terminal FPR5 line and ground.
  • Voltage should be between 4.9 and 5.1 volts.
(4) Turn off the power supply mode of the electric motor switch.
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 the fuel tank pressure sensor connector.
(2) Disconnect all ECM connectors. Connect the power plant ECU check harness special tool MB992110 between the separated connectors.
(3) Turn on the power supply mode of the electric motor switch.
(4) Measure the voltage between terminal FPR5 and ground.
  • Voltage should be between 4.9 and 5.1 volts.
(5) Turn off the power supply mode of the electric motor switch.
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 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 pressure sensor connector and ECM connector.
Is the harness wire in good condition?
Go to Step 7.
Repair the connector(s) or wiring harness. 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 on the power supply mode of the electric motor switch.
(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 off the power supply mode of the electric motor switch.
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 pressure sensor connector and ECM connector.
Is the harness wire in good condition?
Replace the fuel tank pressure sensor. Then go to Step 8.
Repair the connector(s) or wiring harness. Then go to Step 8.
 
STEP 7. Using scan tool (M.U.T.-IIISE), check data list item 211: Fuel Tank Pressure Sensor.
(1) Turn on the power supply mode of the electric motor switch.
(2) Remove the fuel cap.
(3) Set scan tool (M.U.T.-IIISE) to the data reading mode for item 211, Fuel Tank Pressure Sensor.
  • When altitude is 0 m (0 foot), 101 kPa (29.8 in.Hg).
  • When altitude is 600 m (1,969 feet), 95 kPa (28.1 in.Hg).
  • When altitude is 1,200 m (3,937 feet), 88 kPa (26.0 in.Hg).
  • When altitude is 1,800 m (5,906 feet), 81 kPa (23.9 in.Hg).
(4) Turn off the power supply mode of the electric motor switch.
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. 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 1 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P24D7 set?
Repeat the troubleshooting.
The procedure is complete.