Hey guys,

Trouble codes as follows
12 41 42 42 47 24 55

-12 Battery connection disturbed within the last 50 starts
-41 Generator field not switching properly
-42 ASD relay (charging circuit supply) shorted or open, or no ASD voltage at PCM
-47 Charging system voltage too low
-24 TPS shorted or open (Auto only)
-55 Finished with codes

does 42 always flashes twice for some reason? why isn't 24 in numerical sequence? I also don't think the terminals have been touched in past 50 starts, I thought I heard someone else claim this as well.

So obviously there is something up with the altenator. It looks to have been replaced before as it looks relatively new. I'm guessing it has already been converted to the external regulator? It has wires going to the wheelwell with a 2 terminal box, and I forget where that wire goes without going back out to the shop.

Where should I start on this (other than the TPS, I knew about that one, believe me).

And for "Generator field not switching properly".... does that have to do with the exciter, or is that the rectifier that it's speaking of (AC to DC)?

Thanks a bunch guys, you are all the best!!

 

Definatley start looking at the voltage regulation circuts. I got some strange codes while running on the external regulator (don't remember if it was a 41 or 42) of course I had a slap wore out alternator.

 

Swap the ASD relay for one of the other relays on the fender. If that doesn't make it charge, get an alternator.

 

I"ve had no problems starting the ol girl, then again, my batteries are only 3 months old or so.

 

Hey guys, back from sea so I started to look into this...

I saw on another thread while searching that someone said the middle relay is for the starter or something? Anyhow, it was unplugged and the truck has been starting fine since I got back. It only acted a little odd the first time I started it when I was home. Sounded like the bendix gear didn't fully engage the first time I tried, then it was fine. I'll chock that up to sitting for 2 months in some pretty humid weather.

The ASD relay looked a little corroded. I cleaned it up with some electric clean and thought about switching with the A/C (not working) relay, but it was cracked and corroded bad inside. So I guess I"m off to Napa now to get those with some other things. But here is the gist after cleaning the ASD relay a little

Running: 13.6v
Off: 12.9v

That sounds a little low to me for voltage. What do you guys think? The wiring by the PO is a nightmare, and I have a hard time comparing to most peoples pics because mine is hardly EVERY the same! Thanks for any inputs guys, we'll see if she throws a code again on my trip to Ellsworth.

-Luke

 

13.6 is OK, I'd rather see 13.8 but it will keep the battery charged unless you do all short trips.

 

Napa had the relay in the parts book, but nothing in the computer. had to order the relay from Autopart Warehouse or whatever the place is around here.

I seem to notice the voltage falls OFF as RPM's increase. Is this sounding like a voltage regulator problem as well? When I was revving the truck some with the Voltmeter on, it was going down to about 13.5V then back to 13.6v at idle. On the trucks voltmeter it was AFTER the 2nd dash after the 8, and coming back from my trip it was a little BEFORE the 2nd dash after the 8. Pouring rain and the shop is occupied, so I'll check voltages later...

 

Im surprised NAPA did not have the relay. The one in Rockland stocks a single relay and a double relay. I got the double relay for like 25 bucks because the single was 22. They just came on a bracket. I took the bracket off and used the stock brackets.

 

Dang. One of the places had the double relay in stock but I wasn't sure whether I should get it since every parts dude was clueless. They wouldn't have even found the one in the book if I didn't happen to look over as he flipped past the page. The fellow that was at least trying at Napa. He's been there awhile but I think only once or twice a week. Oh well, they were only $8.86 each at the other place.