Fuel System > Engine Control System > P0452 Evaporative Emission System-Pressure Sensor Low Input

Component Location

General Description

The evaporative emission control system prevents hydrocarbon vapors from escaping from the fuel tank into the atmosphere where they could form photochemical smog. Gasoline vapors are collected in the charcoal canister. The Fuel Tank Pressure Sensor (FTPS) is an integral part of the evaporative monitoring system. The PCM monitors the FTPS signal to detect vacuum decay and excess vacuum. The FTPS measures the difference between the air pressure inside the fuel tank and outside air pressure to check the purge control solenoid valve operation and for leak detection in the evaporative emission control system by monitoring pressure and vacuum levels in the fuel tank during the purge control solenoid valve operating cycles.

DTC Description

Checking output signals of fuel tank pressure sensor under detecting condition, if the tank pressure is lower than threshold, PCM sets P0452. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.

DTC Detecting Condition

Item

Detecting Condition

Possible cause

DTC Strategy

•	Detects the signal short to low voltage

•	Poor connection

•	Open in Power Circuit

•	Open or short to ground in signal Cirucit

•	Faulty FTPS

•	Faulty PCM

EnableConditions

•	Ignition ON

Threshold value

•	Raw Tank Pressure < 0.086V

DiagnosisTime

•	Continuous

MIL On Condition

•	2 driving cycles

Specification

Pressure(kPa)	Output Voltage(V)
-3.75	4.5
0	1.5
1.25	0.5

Schematic Diagram

Monitor DTC Status

Check DTC Status

(1)	Connect scantool to Data Link Connector(DLC).

(2)

IG "ON".

(3)	Select "DTC" button, and then Press "DTC Status" to check DTC's information from the DTCs menu.

(4)	Read "DTC Status" parameter.

(5)

Is parameter displayed "Present fault"?

	▶ Go to "Terminal and Connector inspection" procedure.
	▶ Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.

Terminal And Connector Inspection

1.	Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

2.	Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure
	▶ Go to " Power Circuit Inspection " procedure.

Power Circuit Insepction

■ Check voltage

1.	IG Key "OFF".

2.	Disconnect FTPS connector.

3.	IG Key "ON".

Measure the voltage between power terminal of FTPS harness connector and chassis ground.

Specification : Approx. 5V

Is the measured voltage within specification ?

	▶ Go to "Signal Circuit Inspection" procedure.
	▶ Repair open or short to ground in harness and go to "Verification of Vehicle Repair" procedure.

Signal Circuit Insepction

■ Check short to ground in harness

1.	IG Key "OFF".

2.	Disconnect FTPS connector and PCM connector.

Measure the resistance between signal terminal of FTPS harness connector and chassis ground.

Specification : Infinite

Is the measured resistance within specification ?

	▶ Go to "Check open in harness" as follows.
	▶ Repair short to ground in harness and go to "Verification of Vehicle Repair" procedure.

■ Check open in harness

1.	IG Key "OFF".

2.	Disconnect FTPS connector and PCM connector.

Measure the resistance between signal terminal of FTPS harness connector and FTPS signal terminal of PCM harness connector.

Specification : Approx. Below 1 Ω

Is the measured resistance within specification ?

	▶ Go to "Component Inspection" procedure.
	▶ Repair open in signal circuit and go to "Verification of Vehicle Repair" procedure.

Component Inspection

■ Check FTPS

1.	IG "OFF" and connect scatool to DLC(Data Link Connector).

Monitor "FTPS" parameter on service data.

Specificaton :

Pressure(kPa)	Output Voltage(V)
-3.75	4.5
0	1.5
1.25	0.5

Is the "FTPS" parameter on the service data O.K ?

	▶ Substitute with a known - good PCM and check for proper operation. ▶ If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.
	▶ Substitute with a known - good FTPS and check for proper operation. ▶ If the problem is corrected, replace FTPS and go to "Verification of Vehicle Repair" procedure.

Verification Of Vehicle Repair

After a repair, it is essential to verify that the fault has been corrected.

1.	Connect scantool and select "DTC" button.

2.	Press "DTC Status" button and confirm that "DTC Readiness Flag" indicates "Completed". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions

3.	Read "DTC Status" parameter

Is parameter displayed "History(Not Present) fault"?

	▶ System performing to specification at this time. Clear the DTC
	▶ Go to the applicable troubleshooting procedure.