what is involved with CASE Learn
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what is involved with CASE Learn
What is involved with the CASE Learn procedure exactly? Do you really have to bounce the motor off the limiter to do it? If someone can do this for me today i will be very greatfull (just tell me how much $$$). My car is in belleville nj (Exit 150 on the parkway).
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Originally Posted by markp03
whats case learning?
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Anyone with HPT/EFI/TechII can do it. I've done it with HPT, just follow the directions EXACTLY including turning the key off for 15 sec and it works awesome.
CASE relearn has to do with the PCM learning the exact position of the crank sensor/reluctor ring so it can accurately read/predict the position of the crank and detect misfires.
Rob (Bad30th)
CASE relearn has to do with the PCM learning the exact position of the crank sensor/reluctor ring so it can accurately read/predict the position of the crank and detect misfires.
Rob (Bad30th)
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Originally Posted by horist
Dealer has a Tech II (Tech II is GMs official tool... pricey piece of hardware but very nice)
Are you setting an SES telling you to do a CASE Learn?
Are you setting an SES telling you to do a CASE Learn?
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The CASE (Crank Angle Sensor Error) learn procedure records the crank timing signals when there is no firing event. That gives the PCM something against which to compare misfires. If it sees the same (or similar) crank timing when the engine is (meant to be) firing then it records a misfire.
To record the crank timing when no firing event occurs (aka CASE learn), a scan tool is required to instruct the PCM to go into CASE learn mode. The operator is required to increase the RPMs to a preset limit, which is usually around 4,000-4,500 rpm at which point the PCM automatically cuts fuel to engine. While the fuel is cut (for about 1/10th of a second) the PCM records the crank timing.
To record (i.e. save to non-volatile memory) the CASE learn data, you must allow the engine to return to idle and switch off the iginition for about 15 seconds while the PCM "saves" the recorded data.
During specific PCM operating conditions, the crank timing is compared to the saved recording each time a cylinder firing event is expected. If it is different then the firing event is considered successful, if it is the same (or very similar) then the firing event is considered a fail and the cylinder misfire count is incremented. Too many misfire events and a misfire trouble code is set.
Whenever you change the relationship between the PCM, crank reluctor and/or crank sensor, then you must perform a CASE relearn.
Regards
Paul
To record the crank timing when no firing event occurs (aka CASE learn), a scan tool is required to instruct the PCM to go into CASE learn mode. The operator is required to increase the RPMs to a preset limit, which is usually around 4,000-4,500 rpm at which point the PCM automatically cuts fuel to engine. While the fuel is cut (for about 1/10th of a second) the PCM records the crank timing.
To record (i.e. save to non-volatile memory) the CASE learn data, you must allow the engine to return to idle and switch off the iginition for about 15 seconds while the PCM "saves" the recorded data.
During specific PCM operating conditions, the crank timing is compared to the saved recording each time a cylinder firing event is expected. If it is different then the firing event is considered successful, if it is the same (or very similar) then the firing event is considered a fail and the cylinder misfire count is incremented. Too many misfire events and a misfire trouble code is set.
Whenever you change the relationship between the PCM, crank reluctor and/or crank sensor, then you must perform a CASE relearn.
Regards
Paul