P0452

DTC P0452: Evaporative Emission Control System Pressure Sensor Low Input






















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

- 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.
Judgement Criterion

- The fuel tank differential pressure sensor output voltage remains 0.2 volt or less for 5 seconds.

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23 OBD- II Drive Cycle.

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:

- 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 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. 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. Is the sensor operating properly?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.

NO Go to Step 2 .

STEP 2. Measure the sensor supply voltage at fuel tank differential pressure sensor connector D-19 by backprobing.

(1)Do not disconnect the connector D-19.

(2)Turn the ignition switch to the "ON" position.





(3)Measure the voltage between terminal No. 3 and ground by backprobing.

- Voltage should be between 4.9 and 5.1 volts.
(4)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 8.

NO Go to Step 3.

STEP 3. Check harness connector B-11 at ECM for damage.

Q. Is the harness connector in good condition?

YES Go to Step 4.
NO Repair or replace it. Harness Connector Inspection.
Then go to Step 12.
STEP 4. Measure the sensor supply voltage at ECM connector B-11 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 No. 114 and ground.

- Voltage should be between 4.9 and 5.1 volts.
(4)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 7.

NO Go to Step 5.

STEP 5. Check harness connector D-19 at the fuel tank differential pressure sensor for damage.

Q. Is the connector in good condition?

YES Go to Step 6.
NO Repair or replace it. Harness Connector Inspection.
Then go to Step 12.
STEP 6. Check for short circuit to ground between fuel tank differential pressure sensor connector D-19 (terminal No. 3) and ECM connector B-11 (terminal No. 114).

Q. Is the harness wire in good condition?

YES Go to Step 11.
NO Repair it. Then go to Step 12.
STEP 7. Check harness connector D-19 at the fuel tank differential pressure sensor for damage.

Q. Is the connector in good condition?

YES Repair harness wire between fuel tank differential pressure sensor connector D-19
(terminal No. 3) and ECM connector B-11 (terminal No. 114) because of open circuit. Then go to Step 12.
NO Repair or replace it. Harness Connector Inspection.
Then go to Step 12.
STEP 8. Check harness connector D-19 at the fuel tank differential pressure sensor and connector B-11 at ECM for damage.

Q. Is the harness connector in good condition?

YES Go to Step 9.
NO Repair or replace it. Harness Connector Inspection.
Then go to Step 12.
STEP 9. Measure the sensor output voltage at ECM connector B-11 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 No. 112 and ground.

- Voltage should be between 1.5 and 3.5 volts.
(5)Turn
the ignition switch to the "LOCK" (OFF) position.

Q. Is the measured voltage normal?

YES Go to Step 11.

NO Go to Step 10.

STEP 10. Check for open or short circuit to ground between fuel tank differential pressure sensor connector D-19 (terminal No. 1) and ECM connector B-11 (terminal No.
112).

Q. Is the harness wire in good condition?

YES Replace the fuel tank differential pressure sensor. Then go to Step 12.
NO Repair it. Then go to Step 12.
STEP 11. 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 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. 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. Is the sensor operating properly?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.

NO Replace the ECM. When the ECM is replaced, register the ID code. Refer to ID registration procedure manual - ID codes registration judgement table [Vehicles with KOS] or ID registration procedure manual - ID codes registration judgement table [Vehicles with WCM]. Then go to Step 12.

STEP 12. 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 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.