P0451
DTC P0451 EVAPORATIVE EMISSION CONTROL SYSTEM PRESSURE SENSOR1. OUTLINE OF DIAGNOSIS
Detect malfunctions of tank pressure sensor output property by the following two diagnoses.
- DRIFT DIAGNOSIS
To detect drift malfunction and offset malfunction of tank pressure sensor, activate ECM in the predetermined soaking time after turning the ignition switch OFF, and check that the tank pressure sensor input value is equivalent to the barometric pressure.
For vehicles equipped with pressure control valve, be sure to open the pressure control valve when performing the diagnosis, because the pressure inside the tank increases if the ambient temperature rises during soaking.
- Stuck Diagnosis
When there is no pressure variation, which should have occurred in the tank considering the operation status, judge as NG.
2. COMPONENT DESCRIPTION
3. ENABLE CONDITION
4. GENERAL DRIVING CYCLE
[DRIFT DIAGNOSIS]
Perform the diagnosis only once when 3600 s x 3 time(s) has passed after the ignition switch is OFF.
[Stuck Diagnosis]
- Perform the diagnosis continuously after 60 s have passed since the engine started.
- Pay attention to the fuel level and temperature.
5. DIAGNOSTIC METHOD
[DRIFT DIAGNOSIS]
Abnormality Judgment
Judge as NG when one of the following conditions is established.
Time Needed for Diagnosis: 10 seconds
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.
Normality Judgment
Judge as OK and clear the NG if the following conditions are established.
Time Needed for Diagnosis: 10 seconds
[Stuck Diagnosis]
Abnormality Judgment
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.
If the difference between the Max. fuel level every 60 s and Min. fuel level every 60 s is less than 2 (*) (0.53 US gal, 0.44 Imp gal), extend 60 s and make judgment with the Max. and Min. values for the fuel level in 60 s x 2. If there is no difference after the extension of 60 s, continue further to 60 s x 3, 60 s x 4, 60 s x 5. If the difference between the Max. fuel level every 60 s and Min. fuel level every 60 s is 2 (*) (0.53 US gal, 0.44 Imp gal) or more, the diagnosis counter counts up.
Time Needed for Diagnosis: 60 s x 16 time(s) or more
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.
Normality Judgment
Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.
Time Needed for Diagnosis: Less than 1 second