1990 b-250 5.2 v8 new battery,alternator and rebuilt ecm.the code registered on the old computer and continues with the new one?? any ideas would be greatly appreciated.this has stumpedsome auto-electricians. thanks in advance brian martin

 

Is the voltage regulator in the PCM? Or is it a separate module?

 

From the Haynes manual

Chrysler OBD 1
Error code 41 / P0622
DRB Scan Tool Display = Generator Field not switching properly

"An open or shorted condition detected in the generator field control circuit"

Voltage regular is a component of default Nippondenso alternator.

...not saying that's the problem...

Make sure old codes are properly cleared. Must remove battery terminal and there is a specific power off/on protocol.
It was hell to remove a code 51 which I think is still hanging around...

 

to the best of my knowledge the regulator is part of the ecm and is not separate.as i said this code 41has been there with 2 different ecms. brian martin

 

hi rookie thanks for responding.if the voltage regulator is part of the alternator and that was changed it is doubtful to have that same problem again,but it continues.ihave cleared it but it comes back in the next time i drive the van. very confusing

 

hi there i made a mistake with the last post.i believe the voltage regulator is in the alternator and controlled by the ecm.

 

Check the wires from the PCM, to the alternator.

 

The Chrysler manual says that the regulator is a component of the alternator, so there's no guessing where the regulator is. The question is "what causes code 41"?

If it has to do with charging it could be anything in that setup - even as simple as a battery with a bad cell. Right?

The are two other fault codes related to the charging system - 46 for high voltage, 47 for low voltage - so I'd feel pretty sure 41 is not to do with the voltage regulator in this case.

 

Voltage regulator is what controls the field windings. If the alternator is internally regulated, and a replacement didn't solve the issue...... might try another alternator..... But, I keep getting mixed signals on just where the VR is.... some say alt, others say PCM.... I don't have any books for the vans, or anything that old.

And yes, it disturbs me that I think something made in the 90's is "Old"......

 

Here's why, at least from what I'm reading in the Haynes and the 1990 Chrysler Van manual - the VR on the PCM is 1992 and later models. There is a VR on the SBEC (ECM) 1988-1991 which is used with Chrysler alternators. Older models have an external VR mounted next to the ECM.

The Nippondenso which is the default alternator, has its own VR internally integrated. and doesn't rely on the onboard or an external VR.

That's what I've gathered.

My rookie opinion is that it's not the VR. If the VR was out, we'd see voltage out of range which would kick code 46 or 47. Incompatible alternator? I kinda doubt it but hey...

There is also the issue of the bad throttle bodies from this year which causes a hard hot start and rough idle, and it makes the system run in open loop mode. This has an effect on the electrical system.
know that mine runs about 14.2 but on a hot start, it stays at 13.7 and gets reduced fuel economy. I've a speedo that reads volts on the 12v line in real time, so I see it whenever I drive.