Like the title says I've got a 99 2500 been chasing this issue pretty much since I got the truck almost 2 years ago. Long story here I've dug and dug into research on it. Looked at other forums, looked at other pages, seen what worked. I even fixed a few when I worked at dodge by relocating the ground across the radiator. That's what led me to this site when I found out about the alternator AC issue. It made perfect sense seeing as my ECM has a bad microprocessor also. I tried all those bogus tricks. Nothing can seem to fix my truck short of a $3000 manual swap. Only one that really helped was cleaning and replacing bolts on battery terminals for about a week then it came back. I recently changed the diodes having 0.016vAC. I did the wiring mod in the process. I noticed a huge improvement. I'd say 95%. I'm still getting it after I set the cruise it'll do it only once right after vacuum grabs throttle and usually if I accelerate moderately from say 45-55 or 55-65 it'll kick out a couple times. Light throttle won't do it. Feels like same amount of throttle amount every time. Monitoring on scan tool the TC solenoid output in the PCM is still dropping out so I know it's not TC or solenoid. Tps volts look normal on the graph also. I have no doubts the tps volts is filtered so I may not see any system noise but if it lost voltage I'd see it on the graph. I'm wondering if I have an actual APPS issue. If so are aftermarket ones any good? Their electronics are usually junk

3 hours ago, Recian426 said:

I'm wondering if I have an actual APPS issue. If so are aftermarket ones any good? Their electronics are usually junk

When the apps goes bad we recommend the Timbo.  I keep one under my back seat for replacement when the stock one goes bad.   

 You can find it in this sites store section.

 

 

 

I have one on the truck and a spare to boot. It has been trouble free for 10 years. I only have a spare from a misguided repair a while back. 

1 hour ago, dripley said:

I have one on the truck and a spare to boot. It has been trouble free for 10 years. I only have a spare from a misguided repair a while back. 

 

Were you having issues like this to begin with? I have nothing to point at APPS except that it happens at same amount of throttle every time

2 hours ago, Recian426 said:

same amount of throttle every time

May be a dead spot in apps

9 hours ago, Recian426 said:

Like the title says I've got a 99 2500 been chasing this issue pretty much since I got the truck almost 2 years ago.

 

You didn't say how many miles are on the truck.  Is the APPS currently on the truck an OEM part?  If it is the original part or a replacement OEM part with lots of miles, I would consider just replacing it with a Timbo unit.  It may not resolve your problem, but it wouldn't be a waste of money.

 

- John

Truck has 310k and apps appears to be original. It was an old DOT truck so I have no idea what's been done to it aside from the Mopar reman tag on the trans

5 hours ago, Recian426 said:

 

Were you having issues like this to begin with? I have nothing to point at APPS except that it happens at same amount of throttle every time

Mine is a 6 speed and was having surging issues. I was just attesting to the quality of tne u it.

I'd be connecting a decent scanner to it and checking live data to see whats messing about

I did that with my brand new snap-on solus ultra. Don't think I can get any better than that without DRB3. In PCM I can graph the TC signal and TPS volts together and watch live during and that is the reason I know the pcm is commanding the TC off for a split second causing the issue. However TPS volts during this incident seem unaffected

Edited March 25, 20205 yr by Recian426

1 hour ago, Recian426 said:

I did that with my brand new snap-on solus ultra. Don't think I can get any better than that without DRB3. In PCM I can graph the TC signal and TPS volts together and watch live during and that is the reason I know the pcm is commanding the TC off for a split second causing the issue. However TPS volts during this incident seem unaffected

Solus is a good as you'll get, how about checking all other pcm inputs againt tc lockup output to see if anything else is messing about, also on the tps can you effectively zoom in on a solus ? to inspect the signal more closely ??

I briefly glanced over some other inputs but didn't spend alot of time on them. I'm know it can zoom but while driving the truck didn't want to toy with it too much

I think the TC unlocks when the brake pedal is pressed too, not sure. Clean all the battery posts again that used to fix my truck.

W-T ground wire mod and the Alternator protection fuse is my suggested starting spot.

 

 

 

13 minutes ago, Mopar1973Man said:

W-T ground wire mod and the Alternator protection fuse is my suggested starting spot.

 

 

 

I just did the W-T wiring and alternator diodes. Used some good marine grade wiring and hydraulic crimp press. The mod writeup stated the ground mount bolt is a M5 but it's actually a M6. Didn't do the pcm protection but it's something to look into. Not sure if it would cause the issue with TC operation

7 minutes ago, Recian426 said:

Didn't do the pcm protection but it's something to look into. Not sure if it would cause the issue with TC operation

 

When the alternator field shorts to ground on the blue field wire it will completely burn up the PCM. This will cost you about 750 dollars to replace. Not to mention it burns up the voltage regulator completely in the PCM. The fuse will protect the PCM from any damage from bad alternators or wiring faults. Being the master fuse for the PCM is 20 Amp and the circuit board will not tolerate the 20 Amps on the PCB tracers at a dead short. The 5 Amp fuse blows early enough to prevent damage and been proven by another member that had a alternator short out and blow the field fuse.

 

 

 

The fiberglass circuit board is gone there is nothing to repair.

Edited March 25, 20205 yr by Mopar1973Man

The above is well worth doing but won't cause Lockup to drop out, Is there someone else to assist with looking at the solus and driving ?  Also  are you sure that now you've done the WT that what you're seeing is not where it wants to drop out of LU anyway, try it in 3rd lu and see what it does, IIRC mine was on a bit of a knife edge before I fitted a Quad as in a little bit too much pedal and it would drop out.... its different again now as less pedal is needed so stays in longer

Edited March 25, 20205 yr by wil440

I had considered the normal operation kick out based on throttle but it shouldnt unlock and relock within a second right after engaging cruise. It will also under certain throttle and only at certain times, usually when I'm not thinking about it trying to accelerate it'll lock and unlock multiple times each 1 second or so intervals making it hard to actually accelerate. Other times it'll smoothly accelerate with TC staying engaged. Most of the time it's in a nearby place I pass through daily where the speed drops to 45, I stay doing 50 about 2 miles then speed back up to 60. It won't do it climbing a heavy grade hill a few miles later that demands more throttle. It stays locked in. It gets annoying trying to accelerate with traffic in this situation and the Rpms are all over the place about 300 rpm jumps. I can watch 3-4 solenoid and it stays in

You're right it shouldn't do what you describe

Exactly. What throws me is that hill it won't do it. It'll stay in 4th and lockup doing 60 right up that hill with no problems but moderate accel from 50-60 on a flat surface unloaded it isn't happy

If I'm honest I'm not sure what inputs the pcm uses to command LU. There is a trans manual on here but i'm on a phone right now and can't add the link

Its in downloads from menu top right

Edited March 25, 20205 yr by wil440