Ok Gang...I've got a for sure way to diagnose torque converter lock up issues where it lock and unlocks at about 45-50 MPH. I had a gent call me yesterday with this problem and he's replace both batteries, alternator and the APPS sensor. Attempted all the different wiring issues (adding ground, tinfoil etc.) nothing worked. Like I told him the truck ran 11 years without all this stuff and doesn't require any wiring change to make it work. What it needs is the damaged part to be replaced. So he's returned the wiring back to stock setup.Now I told him to unhook the alternator fuse and take it for a ride... Guess what... No problems! Even though he replaced the alternator it has a damaged diode in it and it bleeding AC noise into the electrical system.So before doing any wiring mods, tinfoil, adding grounds, adding filter... PLEASE! Bench test your alternator! This is the second time I've suggested this and both time resolved the torque converter lock up issue.

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PCM, ECM and VP44 grounds are all on the passenger side battery cable. Take a peek you'll see on cable running toward the PCM and cowling. There is no body ground on these units. The only reason for the cheap strap to the PCM is because it mounted into plastic clips the most likely reduce the shielding effect of the case.

Typically if the APPS sensor drop out of range for anytime it "should" throw a P0122 code for low volts because it did drop too low. In your case with the p-pump set up I'm not certain what the other system errors will do to impact the reporting.

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/59-obdii-error-codes-cummins/151-p0122-apps-sensor-signal-voltage-too-low

Monitor & Set Conditions

Accelerator Pedal Position Sensor (APPS) voltage is monitored when engine is running. DTC may be stored if low voltage is detected on APPS signal circuit or low voltage is detected between Engine Control Module (ECM) and Powertrain Control Module (PCM). Possible Causes

• 5-volt Supply At APPS Shorted To ECM Sensor Ground
• APPS Signal Circuit Shorted To ECM Sensor Ground
• 5-volt Supply To Ground
• APPS Signal Circuit Shorted To Ground
• APPS Signal Circuit Open To ECM
• PCM (APPS) Short To ECM Sensor Ground
• ECM (APPS) To PCM (APPS) Circuit Shorted
• ECM (APPS) To PCM (APPS) Circuit Open
• Short To ECM Sensor Ground
• Accelerator Pedal Position Sensor (APPS)
• Engine Control Module
• Powertrain Control Module

Correct the PCM has a wire heading to the battery but on my truck it is within the wiring loom heading to the drivers side.

My battery terminals both have 3 ground leads. One to the body, one to the engine block, one into the wiring loom going heading towards the drivers side (probably to the ECM) and one to the frame. There are a total of 6 ground wires from both batteries.

The PCM needs to have a very good ground. I do not remember what alterations were done on the transmission ground wiring but I do know something was changed to prevent shift hunting.

Edited October 3, 20159 yr by Vais01

Pretty simple just keep your cables clean and in good order. Remember I might own a 2002 Dodge diesel manual but the 1996 is automatic no issues with hunting at all. No extra grounds added to that truck no wiring mods either. It 19 years old and still working fine. Still has the factory 46RE transmission too.

 

My PCM has a ground wire from one of the mounting bolts to the fire wall and the ECM has no separate ground. The only connection to it is the 50 pin connector. This is how it came from the factory.

hello guys .......  working on a 2001.5 dodge diesel 4x4 auto . been driving since 2010 ......

 

anyways while chasing drive line vibration , I ended up  chasing a rabbit down a hole .

 

short version , my multimeter on dc reads 13.8vdc ( reverse the wires and it reads -13.8vdc) , then switch it to ac and it reads around 28 to 30 vac , switch the wires and it reads 0000 .

 

so I am assuming I have a leaky diode .

 

now has anyone thought to add a external rectifier bridge in addiction to what is inside to alternator ?

You need a better multimeter to read the ac volts, that is why you are seeing 30 volts ac.

i was just going to post something alone those lines ...... one multi meter is reading 28 - 30vac , another one is bouncing between .01and .02 volts ac .

i was just going to post something alone those lines ...... one multi meter is reading 28 - 30vac , another one is bouncing between .01and .02 volts ac .

 

That's a valid number what is bold and underlined... The 28-30 is a poor quality meter.

that is what I figured ... thanks  

so the meter i used to was an IDEAL model 61-360.  it started out with a high reading and worked its way back to zero.

 

cheap meter or does this sound right?

 

i think meter was 80 bucks or so new....yrs ago.

It shows to have millivolt ranges so it should work just fine but the high to low volt reading is rather odd.

after it gets to zero...it stays there...maybe even a little negative. id have to check again for the negative part....but definitely from high to low

There is no positive or negative to AC voltage being its a sine wave going positive to negative. Here a video of what it looks like.

I have 2001 2wd Auto as my daily work truck.  I am starting to have the lock/unlock issue too.  I did the voltage test, got 14.2-3 VDC and anywhere from .5 to 0 VAC.  It would go to zero unless a load cycled then it would go up to .03-05 VAC then settle back to zero once the load cycled off. 

 

I did the cable checks first and everything was 0 or .01 VDC drop which is fine.

 

I am assuming that since this probnlem is intermittent that I may be catching the failure at it's starting point.  Since it is intermitten, I am not sure removing the fuse and test driving it will tell me anything since it is not constnatly happening. 

 

I have a new alternator on the way.

 

EDIT:  this only occurs occaisionally when at steady state 40-45 mph which is about 1300 rpm in overdive and a slight load occurs such as a little bit if a grade increase.  As soon as you step on it, it goes away.

 

Any thoughts?

Edited October 11, 20159 yr by Bryan

Another way of testing for the problem. Unhook both BATT wire and field. Make sure to pull the Alternator fuse to make sure of no shorts occur. Now go for a test drive. I bet money the lock / unlock goes away.

so couple weeks ago, i pulled the wrong fuse.  reinstalled it.  now the hunting has gone away....in OD.

now i get TC hunting in 3rd....and i believe down shifting to 2nd.  im noticing the downshift tends to happen when going over bumps....as little lane reflectors.

i still have the knocking sound.  running the edge comp box OFF.  made no difference in sound, just performance.  i usually have it on 1...2 if im feeling frisky.  i dont feel confident enough to go higher or even rev it high.  vary rare i go over 2k rpm.

i like the truck...just gotta chase the goblins around some more.

Another way of testing for the problem. Unhook both BATT wire and field. Make sure to pull the Alternator fuse to make sure of no shorts occur. Now go for a test drive. I bet money the lock / unlock goes away.

so couple weeks ago, i pulled the wrong fuse.  reinstalled it.  now the hunting has gone away....in OD.

now i get TC hunting in 3rd....and i believe down shifting to 2nd.  im noticing the downshift tends to happen when going over bumps....as little lane reflectors.

i still have the knocking sound.  running the edge comp box OFF.  made no difference in sound, just performance.  i usually have it on 1...2 if im feeling frisky.  i dont feel confident enough to go higher or even rev it high.  vary rare i go over 2k rpm.

i like the truck...just gotta chase the goblins around some more.

Ahh... Come on you got to sample the 5x5 once some day.

 

Seriously though...

 

Something to be aware of is that you got to get into the power once in awhile for couple of reasons. First you need to be able to exercise the wastegate on the turbo once in awhile or it will rust shut. Very common on trucks where people are afraid to use the power once in awhile. Also it good to get the pyrometer up to1,100 to 1,200*F and hold it for few miles to cook off all the carbon in the cylinders, pistons and injectors. So even if you leave the level low you need to work the truck once in while to exercise different system and rid the carbon build up.

I have 2001 2wd Auto as my daily work truck.  I am starting to have the lock/unlock issue too.  I did the voltage test, got 14.2-3 VDC and anywhere from .5 to 0 VAC.  It would go to zero unless a load cycled then it would go up to .03-05 VAC then settle back to zero once the load cycled off. 

 

I did the cable checks first and everything was 0 or .01 VDC drop which is fine.

 

I am assuming that since this probnlem is intermittent that I may be catching the failure at it's starting point.  Since it is intermitten, I am not sure removing the fuse and test driving it will tell me anything since it is not constnatly happening. 

 

I have a new alternator on the way.

 

EDIT:  this only occurs occaisionally when at steady state 40-45 mph which is about 1300 rpm in overdive and a slight load occurs such as a little bit if a grade increase.  As soon as you step on it, it goes away.

 

Any thoughts?

Got my new alternator today.  Took a Bosch off and the replacement was a Denso.  After replacing the alternator, the test result was 0.00 to 0.015 VAC.

Another way of testing for the problem. Unhook both BATT wire and field. Make sure to pull the Alternator fuse to make sure of no shorts occur. Now go for a test drive. I bet money the lock / unlock goes away.

I will road test tomorrow.  I am pretty sure that solved the problem.  I did check the alternator brushes for the field and they were pretty well worn along with a lot of scoring and grooving on the slip rings.   Not sure if they contributed, but I am sure that didn't help anything either.

I'm hoping someone can help me out with my TC lockup issue, I'm at my wit's end. Truck is a 98.5 24v, only real modifications are a BHAF and Edge EZ. Trans was rebuilt about 100k ago with billet torque converter and full R&R.

I've been chasing a locked torque converter issue for months. After researching the issue I tried a number of different fixes. Flushed and filled the trans, pulled the valve body and inspected, replaced lockup solenoid, checked lockup spring, bypassed the trans cooler, and finally checking for AC noise. Upon checking for noise, I used a cheap DV and came up with 30V AC. Used a Blue Point Pen-Probe style DVM and the AC voltage fluctuated and was well over 0.1VAC. Replaced alternator with O'Reilly reman and same readings. Returned that reman and put in the existing alt.

Removed the 140A fuse for the alternator and issue remains. Seperated the ground from the loom on the back of the alternator and covered with aluminum foil. Issue remains. I tried adding another ground from the battery to the body of the alternator, no change. I then tested the system, with the 140A fuse for the alternator removed, and there is still 2.48V AC at the bridge of the fuse and fluctuating at the battery terminals. What is going on??? How is there AC noise when the alternator fuse is removed?

Couple more details - the TC will lock and unlock. Not on the highway, it's usually fine there. When cold, it behaves normally. After warming up, the TC will lock. It also will unlock randomly and stay unlocked for a little while. If I turn the truck off while it's unlocked, then start again, the TC will usually lock. Is my PCM toast? ECM? Did my alternator fry everything already? The VP44 and lift pump were replaced about 40k ago. Help!