With this being March, ambient temperatures in most of the US & Canada start to climb to the minimum ambients required for systems to perform EVAP self diagnostics and thus spring & fall are the most prevalent times of the year we see evap failure codes.
The systems just won't self test in the cold of winter, nor the high heat of summer.
While it may be obvious to some, it may not be obvious to others that there are pids that we need to monitor in order to PROPERLY test evap system failures.
This is from an article that was speaking of an import vehicle evap system but it is still true for almost any vehicle I have encountered or read about.
"The quickest way to run any monitor is to control as carefully as
possible the critical enabling criteria of road speed, fuel level and coolant
and air intake temperature."
Kinda hard to control those parameters if we can't see the pids so we know what the ECM/PCM is seeing and thus what it is going to try to do.
The systems just won't self test in the cold of winter, nor the high heat of summer.
While it may be obvious to some, it may not be obvious to others that there are pids that we need to monitor in order to PROPERLY test evap system failures.
This is from an article that was speaking of an import vehicle evap system but it is still true for almost any vehicle I have encountered or read about.
"The quickest way to run any monitor is to control as carefully as
possible the critical enabling criteria of road speed, fuel level and coolant
and air intake temperature."
Kinda hard to control those parameters if we can't see the pids so we know what the ECM/PCM is seeing and thus what it is going to try to do.
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