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.
Checking output signals
from FTPS under detecting condition, if the FTPS indicates pressure
momentarily increased more than 5.6 reading displaying on scantool, PCM
sets P0454. MIL(Malfunction Indication Lamp) turns on when the malfunction
lasts till consecutive 2 driving cycle.
Item
|
Detecting
Condition
|
Possible cause
|
DTC
Strategy
|
| •
|
Monitors the fuel tank
pressure | |
|
EnableConditions
|
| •
|
Intake Air Temperature ≥ -4°C( 24.8
°F) |
|
Threshold
value
|
| •
|
Tank Pressure > 5.6 reading
displaying on scantool | |
DiagnosisTime
|
| •
|
Continuous
(Within 10
sec.) | |
MIL On
Condition
|
|
Pressure(kPa)
|
Output
Voltage(V)
|
-3.75
|
4.5
|
0
|
1.5
|
1.25
|
0.5
|
| 1. |
Check DTC Status
| (1) |
Connect scantool to Data Link
Connector(DLC). |
| (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. |
| 3. |
Has a problem been found?
|
|
▶ Repair as
necessary and go to "Verification of Vehicle Repair"
procedure
|
|
|
▶ Go to "
Component Inspection "
procedure
|
|
■ Check FTPS
| 1. |
IG "OFF" and connect scatool to DLC(Data Link
Connector). |
| 2. |
Monitor "FTPS" parameter on service
data.
Specificaton :
Pressure(kPa)
|
Output
Voltage(V)
|
-3.75
|
4.5
|
0
|
1.5
|
1.25
|
0.5
|
|
| 3. |
Does the "FTPS" parameter change after
accelleration ?
|
|
▶ Fault is
intermittent. Drive the vehicle to satisfy the enable codition
then, 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 |
| 4. |
Is parameter displayed "History(Not Present)
fault"?
|
|
▶ System
performing to specification at this time. Clear the
DTC
|
|
|
▶ Go to the
applicable troubleshooting
procedure.
|
|
