No charge avenger

Christopher Diagnostician Wyoming, Michigan Posted   Latest  
Question
Electrical
2009 Dodge Avenger R/T 2.4L (B ED3) 4-spd (40TE)—1B3LC56B49N553746
P0622 - Generator Field/F Terminal Circuit

Alternator not charging. Voltage at main battery wire is equal to battery. Case ground good. Below .04mv running. Sensing wire shows within 1 volt of battery(lower) at alt and pin of pcm and matches scan data. Correct according to A.D. Control wire voltage fluctuates but never gets above 2 volts command. Reads same at alt and pin of pcm. If battery voltage applied to control wire alternator will charge at 18-19 volts. Customer states he has installed remanufactured alt and pcm with no change. I have verified both pcm's (original and remanufactured) operating with the same control output. At a bit of a loss as alternator is capable of output and pcm is trying to control output and wiring passes voltage drop test. Would call it pcm as control seems low but both pcm's show same control voltage. Will check pin fitment and pcm powers and grounds in the morning as I ran out of time today. Any thoughts are welcome. Thank you.

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Caleb Diagnostician
Mishawaka, Indiana
Caleb Default
 

You need to put a scope on the control wire to the alternator. The generator control in the PCM is a 0-12 volt square wave that varys duty cycle depending on voltage demand. The generator control driver in these era Chrysler PCMs have are strong enough to brightly light a regular incandescent test light. I would scope the control with the alternator connected and disconnected while loading it…

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Stephen Owner/Technician
Dublin, California
Stephen Default
 

I've heard of this before, and there are two possible alternators. The dealer will confirm if that's the case. if I recall, internally they are wired differently. Externally though they look the same and the connectors fit as such

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Mohammad Owner/Technician
Champaign, Illinois
Mohammad Default
 

"I've heard of this before, and there are two possible alternators. The dealer will confirm if that's the case. if I recall, internally they are wired differently. Externally though they look the same and the connectors fit as such" The only difference between the two alternator for the above application (09 Avenger with 2.4L) are only their output at 115 and 140 amp, Both are made by…

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Caleb Diagnostician
Mishawaka, Indiana
Caleb Default
 

Thanks for this info. Its nice to have the 400hz tidbit!

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Christopher Diagnostician
Wyoming, Michigan
Christopher Resolution
 

Thank you caleb for reminding me to k.i.s.s. used graphing meter 1st time rather than scope. Could see pcm activate with scope until code set then drop to a couple volts. Didn't think to use test light to bypass. What really threw me was the fact alternator worked at full field. Both old and remanufactured alternators were bad. 3rd alternator fixed it. Thank you Stephen for your reply. I did…

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Caleb Diagnostician
Mishawaka, Indiana
Caleb Default
 

Cool,glad you got it man!! This is why I love a scope and test light lol.

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