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p0502 when launching under boost

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Old Aug 25, 2010 | 11:10 AM
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Default p0502 when launching under boost

If i want to race someone and i line up to them, ill stall truck up in first till it barely makes boost then leave hard but trans will go into limp mode and pull this p0502 code which is vss. If i just leave hard without boosting it does fine. I dont get it. When it goes into limp mode ofcourse i lose the race cause it shifts into second and thats it. Im gonna change out the sensor first and see what happens.
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Old Aug 25, 2010 | 01:30 PM
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When the pcm detects a low vehicle speed with a high engine speed in a drive range, then p0502 will set.
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Old Aug 25, 2010 | 01:32 PM
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Something i need to fix with hp tuners?
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Old Aug 25, 2010 | 01:41 PM
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My truck doesn't do that when I launch under boost, so I don't believe it to be "normal". It's probably wiring, or a sensor. Maybe this will help you.

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Old Aug 25, 2010 | 01:54 PM
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I just re-read the conditions for setting the DTC, I don't stall up past 2000 rpm, so I guess it's apples & oranges.

If you're stalling over 3000 rpm for over 3 seconds, the DTC may set. Here's the first half of the printout off Mitchell.



Maybe you can use HPT to adjust something. Says "torque between 40-400 ft lbs. Maybe max allowed torque settings need increased? IDK.
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Old Aug 25, 2010 | 02:21 PM
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Hmm thats weird. Ill bring it up to my tuner tonight. Thanks. Any other inputs?
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Old Aug 25, 2010 | 05:39 PM
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Yep...one of theconditions for setting p0502 is engine speed over 2900 rpm's for over 2.5 seconds
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Old Aug 25, 2010 | 05:55 PM
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Code is getting turned off tomorrow.
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