Over the last couple of weeks I noticed my TC was acting weird.  When its engaged over 45mph and I hit the brakes the TC disengages like its supposed to but then immediately reengages as soon as I let off the brake and its a noticeable reengagement.  It has never done that before.  It would always stay off unless I got back on the gas pedal.  I scanned for codes and it had 2 codes.  One for APPS low voltage and one for charging system low.  So I bought a new Timbo APPS and installed it today.  The TC is still acting the same.  I checked the alternator and it is charging normally.  I did notice that the AC voltage is up though.  When I first did the WT mod the AC noise was at almost nothing but now its at .05 VAC.  I may have to replace the alternator again.  This ones only about 2 years old.  Anything else you can think of that would cause the TC to act like this?

 

I also have another question.  If I go with a Nations alternator (I want a better quality alternator) will I have to get a different breaker.  I currently have a 150 Amp breaker installed but the Nations Alternator is 180 Amp.  I'm guessing the 150 amp breaker will be good as the truck shouldn't draw over the 136 Amps that the OEM alternator is rated for unless something is wrong or I add something that would draw more power.

 

 

1. Pull both batteries and have tested, if any batteries fails replace BOTH BATTERIES!
2. Pull the alternator have it tested. If the the alternator fails the AC ripple test replace.
3. Clean and check all main cables and check voltage drop. Like myself main ground cables have 0.003 to 0.005 (3 to 5 mV DC drop).
4. If the W-T ground wire mod isn't done you best do it now. This will stop that entire mess in this one mod. 

 

Once you do the W-T ground wire mod you won't need an upgraded alternator.

 

I'm still running factory alternators, the only different thing I've done is reduced alternator loading with Morimoto HID headlights (2.5 Amps), PIAA LED Driving Lights (1 Amp), and all exterior lights are LEDs now. Even the interior lights are LED inside the cab, still got to do the cluster lights yet. Eventually I remember to change my fuses in the cab and PDC to smaller fuses being taillights are like (1 amp) DC light up being each bulb is like 250 mA (0.25 amps). 

 

12 hours ago, Mopar1973Man said:

1. Pull both batteries and have tested, if any batteries fails replace BOTH BATTERIES!
2. Pull the alternator have it tested. If the the alternator fails the AC ripple test replace.
3. Clean and check all main cables and check voltage drop. Like myself main ground cables have 0.003 to 0.005 (3 to 5 mV DC drop).
4. If the W-T ground wire mod isn't done you best do it now. This will stop that entire mess in this one mod. 

 

Once you do the W-T ground wire mod you won't need an upgraded alternator.

 

I'm still running factory alternators, the only different thing I've done is reduced alternator loading with Morimoto HID headlights (2.5 Amps), PIAA LED Driving Lights (1 Amp), and all exterior lights are LEDs now. Even the interior lights are LED inside the cab, still got to do the cluster lights yet. Eventually I remember to change my fuses in the cab and PDC to smaller fuses being taillights are like (1 amp) DC light up being each bulb is like 250 mA (0.25 amps). 

 

My AC noise at the alternator is .05

My cables are all new.  Just replaced them this past summer

W-T Ground Mod is done already.  Been done since about the time I replaced the alternator.

I havent had the batteries checked.  They've been in the truck since I bought it.  I will pull those and have them tested.

 

I still think I need to replace the alternator with it putting out .05 VAC... 

Check the state of the G100 ground to the front of the drivers battery tray, I had a left turn signal working the wipers which was the G100 ground, BUT since sorting it out lockup is different, I have problems with lockup shuddering if I pedal it but since re doing the G100 it is better, not fully sorted my problem but better, my torque  and trans really need  £££ thrown at them

Typically the PCM is in control of the lockup issue and it ground is the passenger battery terminal. I splits off and goes to the driver side for ECM and VP44. The other runs back towards the firewall for the PCM. All the other body grounds are subsystem like the one near the driver battery is mostly lighting and the ABS computer on that one. 

I don't care a hoot what is grounded on G100 what I do know for sure is cleaning that up has reduced my torque convertor problems

That's what weird... Now you got me scratching my head be cause no main computers (ECM or PCM) use body grounds. (G100)

• ECM is grounded on G125
• PCM is grounded on G123

 

G100 shown below.

As I said in my original last post on my left turn/ wiper problem I can be accelerating harder in L/U after cleaning up the G100 before the lockup clutch starts to chatter/slip, nothing else has changed and it is in either 3rd L/U or 4th L/U, I can now actually stomp it to force a L/U dropout, I had to be very careful before fixing G100 getting it to drop out of L/U, thinking about it I'd be pedalled off.

A/C voltage is low, wt is done, I've looked at the schematic and I cannot figure it out, only thing I can think of is stuff must have been finding ground somewhere else.

Maybe 6 years ago I did a Caterpillar certified series of courses, Engines, Trans, Hydraulics and Electrics, the electrical was 10 days, the first thing the instructor said was electrical Ions flow from the ground not the positive which was totally the opposite to what everyone thought on this course  ( don't shoot me Only repeating)

On these trucks I'd go so far as checking the box ground strap for a vp issue

 

I'll check that ground when I pull the batteries to have them tested. 

 

Here is how to fix the PCM grounds

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/51_engine/electrical/pcm-ground-splice-repair-r675/

1 hour ago, hdpwipmonkey said:

I'll check that ground when I pull the batteries to have them tested. 

 

and if it isn't your problem at least you'll have ticked off a ground that is very prone to corrosion 

Problem solved!

 

Believe it or not, 2 new batteries fixed it.  I stopped at the Interstate store on my way home from work and had them load test the batteries.  The passenger side was not able hold a load.  The drivers side didnt fail but based on others comments on the forum I replaced them both.  I had not figured that just replacing the batteries would have an effect but low and behold after installing the batteries I took it for a test drive yesterday and no more TC issues 

 

I have not checked the AC noise after replacing the batteries, wonder if that issue is fixed too...

On 2/21/2021 at 7:51 AM, wil440 said:

As I said in my original last post on my left turn/ wiper problem I can be accelerating harder in L/U after cleaning up the G100 before the lockup clutch starts to chatter/slip, nothing else has changed and it is in either 3rd L/U or 4th L/U, I can now actually stomp it to force a L/U dropout, I had to be very careful before fixing G100 getting it to drop out of L/U, thinking about it I'd be pedalled off.

A/C voltage is low, wt is done, I've looked at the schematic and I cannot figure it out, only thing I can think of is stuff must have been finding ground somewhere else.

Maybe 6 years ago I did a Caterpillar certified series of courses, Engines, Trans, Hydraulics and Electrics, the electrical was 10 days, the first thing the instructor said was electrical Ions flow from the ground not the positive which was totally the opposite to what everyone thought on this course  ( don't shoot me Only repeating)

On these trucks I'd go so far as checking the box ground strap for a vp issue

 

W-T been drillin me lately and I know he would agree. Electrons are flowing from the negative to the positive. Negative is loosing and positive is gaining electrons. Kinda like this website is positive cause everyone leaves the dealership (negative) and flows to Mopar1973Man (positive).

 

BTW hdpwimonkey, that is a nice truck you have and glad you found the problem. 

Edited February 23, 20214 yr by JAG1

Basic electrical theory. 

Well, I guess I was too quick to say it was fixed.  It started doing the hard unlock and relock when I hit the brakes again on the way home from work today.  It's weird that it was fine for a couple of days after replacing the batteries.  The search continues...

This kid nda tells me still problem with wires, you messed with them and everything was fine now it's back. I'd make sure all connections are in good shape. Make sure ac is below .03vac these trucks really don't like ac noise and bad connections. I've had my shear of  on electrical gremlins and in the end after WT and other mods it's seems fine now. I do have to kick the tire every so often just to let the truck know I'm paying attention. These things are alive, no attention they run like crap, too much attention they break for no reason, kicking a tire few times a week keeps it happy. 

I dealt with electrical gremlins for 3.5 years before changing the cables and then WT's ground mod. Plus a bad splice in the 5v sensor signal. I have been clean of them for about 3.5 years and now brake gremlins. It was good 3.5 years anyway.

I did the W-T mod but I used crimp connectors   I am going to remove those and do a good solder on them instead.  I did see my AC noise is up to 0.05 now and it used to be around 0.001, again could be from a bad connection on the grounds from the W-T mod.

 

I think I am going to pull the plugs on the PCM and make sure there is no water or anything in them too, we had a decent snowfall here around the time this started and I'm wondering if the snow melted and somehow ran down into the PCM 

 

I will keep you all up to date with my findings.  I will make sure I kick the tire a few times too 

52 minutes ago, hdpwipmonkey said:

I think I am going to pull the plugs on the PCM and make sure there is no water or anything in them too,

Get a large size tube of dielectric grease and coat all the connections before plugging them back together.  This will help keep the high ohm resistance gremlins at bay.

 

I did my ground connections like this then slid the prepositioned heat shrink cover over it for insulation. 

 

 

6 hours ago, hdpwipmonkey said:

Well, I guess I was too quick to say it was fixed.  It started doing the hard unlock and relock when I hit the brakes again on the way home from work today.  It's weird that it was fine for a couple of days after replacing the batteries.

 

Actually, that is not weird at all, in fact it is normal when there is stray voltage interfering with electronic components.  For example, the PCM receives inputs (some wanted and some not) and makes decisions based on these  inputs, such as when the torque converter should be locked or unlocked.  When stray voltage influences these inputs, the PCM temporarily keeps track of them and determines whether or not to use them or discard them.  If the stray voltage signals are frequent enough in a specific time period, the PCM will use these inputs along with the wanted inputs and make decisions accordingly.  That's when the bad behavior shows up.  When you replaced the batteries, the PCM lost all of this temporary information regarding the stray voltage inputs while the batteries were disconnected.  So, that is why it took a couple of days for the problem to resurface.

 

- John

Edited February 25, 20214 yr by Tractorman
'cause I always forget something...

What's lockup like when you drop it in and out of 4th, is it still harsh or not