The PCM sets DTC P0451 when an improper voltage signal from EVAP control system pressure sensor is sent to Engine Control Module (PCM).
Item | Detecting Condition | Possible Cause | |
Case 1 | DTC Strategy |
•
Pressure sudden change(Oscillation check) | 1. Poor connection 2. Faulty FTPS 3. Damaged wiring 4. Faulty PCM |
Enable Conditions |
•
Vehicle speed less than 19mph
•
AAT(Ambient Air Temperature over and equal 0℃(32°F)
•
Debouncing time for CCV opening greater than 25sec | ||
Threshold Value |
•
Variation of FTP(Fuel Tank Pressure) greater than 2.5kPa | ||
Diagnostic Time |
•
15sec | ||
Case 2 | DTC Strategy |
•
Rationality, high or low | |
Enable Conditions |
•
Time after engine start greater than 25sec
•
BARO greater than 74.6kPa(0.746bar/10.8psi)
•
AAT(Ambient Air Temperature) greater than and equal 0℃
•
Fuel level greater than 6.5L and less than 36.5L
•
Debouncing time for CCV(Canister Control Valve) opening greater than 25sec | ||
Threshold Value |
•
FTP greater than 3.5kPa(high)
•
FTP less than -3.5kPa(low) | ||
Diagnostic Time |
•
14sec | ||
Case 3 | DTC Strategy |
•
Signal stuck diagnosis during PCSV opening | 1. Poor connection 2. Faulty FTPS 3. Damaged wiring 4. Faulty PCM |
Enable Conditions |
•
AAT(Ambient Air Temperature) over or equal 0℃(32°F)
•
Vehicle speed equal 0mph
•
Intake manifold pressure/BARO less than and equal 0.62
•
Tank pressure greater than -3.4kPa and less than 3.4kPa
•
BARO greater than 74.6kPa(0.746bar/10.8psi)
•
Fuel level greater than 6.5 and less than 36.6L
•
Variation of Purge mass flow greater than 1.8kg | ||
Threshold Value |
•
Variation of FTP(Fuel Tank Pressure) less than 70Pa | ||
Diagnostic Time |
•
15sec | ||
Case 4 | DTC Strategy |
•
Rationality, offset error | |
Enable Conditions |
•
AAT greater than -6.8℃(19.76°F)and less than 42℃(107.6°F)
•
BARO greater than 74.5kPa(0.745bar/10.8psi)
•
Fuel level greater than 15% and less than 85%
•
Vehicle speed greater than 9.3mph and less than 55mph
•
Filtered FTP deviation less than 200Pa
•
Integrated purge mass greater than 10g
•
Refueling condition Not detected
•
PCSV(Purge Control Solenoid) and CCV(Canister Control Valve) plausibility check result OK or No error of CPSV & CCV after Leak monitoring No error | ||
Threshold Value |
•
Tank Pressure greater than 1kPa or less than -1kPa | ||
Diagnostic Time |
•
5sec | ||
Enable Conditions |
•
PCSV and CCV plausibility check : OK criteria
•
After PCSV and CCV plausibility check
•
Deviation FTP between (a) and (c) less than 50Pa
•
FTP in (a) - min FTP in (b) greater than 100Pas (CPSV and CCV plausibility check procedure) (a) Tank pressure check (purging inactive) Intake manifold pressure/BARO less than 0.6 (b) Tank pressure check (purging active) Purge mass flow greater than 0.8kg/h (c) Repetition of (a) | ||
MIL ON Condition |
•
2 driving cycles | ||
