Engine/Transmission (1998.5 - 2002) Newby with a big problem

[deadon]

Sorry my first post is needing help rather than helping someone but thats the way it is.

I have a 99 dodge 2500 turbo deseil. About six mos ago she started shifting in and out of gear violently at 40 MPH. I had the transmission rebuilt for 2500. 00 then I replaced the lift pump the turbo pump the TPS and the drive train computer on the side of the engine block. Everyone I talked to said it was something different. I finally found an electric specialist who had the correct annalizer and he said I had low voltage to the TPS. If I could find the plug he would make me a new wiring harness and that would solve the problems.

Guess what, they don,t make it any more.

Any help would will be greatly appreciated.

 

[Tractorat]

Have you tried a junk yard ?

 

[BoeingDiesel]

Deadon, first it would be helpful for you to provide a truck profile including any mods’ you have added to the truck. Your description of the truck going in and out of gear sounds more like you have been struck with the T/C lock unlock scenario. Question; does it continue to do this as you accelerate and does it level out above 65 mph? New ECM wiring harness?? Suggestion; clean all battery terminals and connectors, you may find this will give you some temporary relief. There are lot more things that you can do to your truck if it is the T/C cycling in and out so I strongly recommend you try this first to narrow the field.

Good luck

gregg

 

[DavidC]

ECM (Engine Control Module) is on engine block. PCM (Powertrain Control Module) is on passenger side firewall.

Dave

 

[DavidC]

Here is your wiring diagram. Unless the wiring is damaged, bad splice etc. I highly doubt it is bad. You would need to check voltage to ground at the ECM and TPS to verify voltage. I would personally try running a seperate ground from the TPS to the battery and see if that solves it.

 

[DavidC]

You may want to look at this also
https://www.atsdiesel.com/PDF/120505/4th hunt 46 47 RE.pdf

Dave

 

[deadon]

Tractorrat, I checked all junk yards within a hundres miles of my home.

Boeingsiesel, A flter was installed between the TPS and the module on the firewall when the transmission was rebuilt and sometime in the past someone ran a ground wire between the TPS and the battery.
I only kicks in and outta gear when i am cruising. Accellerating and coasting it does not.

Davidc, Thanks for the wireing diagrams, That is how my mecanic found the filter and the ground wire.

Still at a loss.

Any other ideas??????

Thanks to all, deadon

 

[cerberusiam]

The question is low AT the TPS or low voltage FROM the TPS to the PCM. There is a significant difference in the source of the problem and need to get that clarified. If you have low voltage to the TPS then the wiring can be checked from the ECM to determine if it is wiring or ECM. Since you replaced the ECM already the problem is likely elsewhere. Clarify the violent shifting, is it dropping lockup and OD, or, just lockup?

If you have low voltage or fluctuating voltage from the TPS at the PCM, take the filter out and throw it as far as you can. The filter going bad will drop voltage and cause all kinds of issues. It is totally worthless for anything but a potential problem maker. There are basically 2 things that cause the voltage fluctuation adn the lock\unlock or even randomly dropping OD, noice in the system or voltage going low to the PCM. Noise can usually be eliminated by removing the ground wire from the passnger side battery to the ECM from the main harness, and, removing the alternator charge wire from the main harness. That would be where I start on issues like this.

The last one nobody likes to hear, but, the FPCM on the IP can cause these problems. You may have to replace the VP-44 to solve the problem. You did not say if you were getting codes, need to check for them with a good scanner to make sure you don't have an indication of the problem.

 

[deadon]

The question is low AT the TPS or low voltage FROM the TPS to the PCM. There is a significant difference in the source of the problem and need to get that clarified. If you have low voltage to the TPS then the wiring can be checked from the ECM to determine if it is wiring or ECM. Since you replaced the ECM already the problem is likely elsewhere. Clarify the violent shifting, is it dropping lockup and OD, or, just lockup?

If you have low voltage or fluctuating voltage from the TPS at the PCM, take the filter out and throw it as far as you can. The filter going bad will drop voltage and cause all kinds of issues. It is totally worthless for anything but a potential problem maker. There are basically 2 things that cause the voltage fluctuation adn the lock\unlock or even randomly dropping OD, noice in the system or voltage going low to the PCM. Noise can usually be eliminated by removing the ground wire from the passnger side battery to the ECM from the main harness, and, removing the alternator charge wire from the main harness. That would be where I start on issues like this.

The last one nobody likes to hear, but, the FPCM on the IP can cause these problems. You may have to replace the VP-44 to solve the problem. You did not say if you were getting codes, need to check for them with a good scanner to make sure you don't have an indication of the problem.

The violent shifting in and out of gear stopped when I had the transmission rebuilt. Now it goes in and out of gear cruising at all speeds. I see the tack going up maybe 50 MPH and back as it goes back into gear. If I accelerate it does good but then holding it at the cruising speed it will go in and outta gear again.
The code said "low voltage to the TPS"

Thank you Sir, Don't know what to do next, Deadon

 

[cerberusiam]

The tach reads rpm's not mph, I assume you are seeing a 50 rpm jump wich would make a lock\unlock problem. Start with this :

Noise can usually be eliminated by removing the ground wire from the passnger side battery to the ECM from the main harness, and, removing the alternator charge wire from the main harness. That would be where I start on issues like this. If you have low voltage or fluctuating voltage from the TPS at the PCM, take the filter out and throw it as far as you can.

Did you get an actual code and is it still there? Your original post said an electrician told you it was low voltage not a code, it matters whether there is a code or an opinion. You are going to have to start tearing things apart to find the problem. The truck is 14 years old, at some point the wiring shielding starts breaking down and noise causes a lot of problems.

 

[JLandry]

deadon,



Have you replaced the alternator yet with a NEW one (not a rebuilt)?



I ask because a worn alternator can be a significant source of electrical "noise" in the DC circuits which can lead to the transmission torque convertor randomly locking and unlocking.



John L.

 

[deadon]

Tidewater auto electric hooked up their analizer and the code said "low voltage to the TPS

Thanks again to all

 

[JLandry]

Tidewater auto electric hooked up their analizer and the code said "low voltage to the TPS

I'd recommend you buy or borrow a simple OBDII code scanner, read and write down any DTC's (Diagnostic Trouble Codes) yourself, then post them here so we can provide you with better Dodge-specific troubleshooting procedures. We need to know the exact DTC number(s) and don't care about the name(s) or description(s).



Many auto parts stores will lend you an OBDII scan for free.



Regards,



John L.

 

[deadon]

I'd recommend you buy or borrow a simple OBDII code scanner, read and write down any DTC's (Diagnostic Trouble Codes) yourself, then post them here so we can provide you with better Dodge-specific troubleshooting procedures. We need to know the exact DTC number(s) and don't care about the name(s) or description(s).

Many auto parts stores will lend you an OBDII scan for free.



I will do as you suggest.

My mechanic has a snap on scanner which showed no codes. When I called tidewater auto electric they said a lot of the parts on the 99 was 99 only and they had the program that would pick up the codes. The annalis cost me 300. 00.

Thanks again, Rusty

 

[DavidC]

Wow, 300. 00. Autozone reads them for free. I have the software on my laptop to read mine. Maybe I should start a business

Dave

Dave

 

[DavidC]

Here is the possible codes you may have. I would get a scanner as noted above and stay away from your specialist. Ask around here first as there are very knowledgeable people here and you will have more money to buy tools and trouble shooting devices and still be money ahead.

Dave

 

[deadon]

Ok fellows I am back with the same problem. My check engine light went off foe three weeks. When it came back on I went to auto zone and they hooked up their annalizer and said "something is preventing them from getting to read any codes, check all connections and fuses". We did and all is well but truck still broke.



The guy who runs the storage facility hooked up his brand new annalizer and the code was PO122 and he printed out this list of everything we could chectout. There were 12 items on the list and they all checked good but truck still broke.



My mechanic/friend hooked up his annalizer and two more codes came up. They are P1682 and P1693. Please tell me what to do next other than get a new truck or shoot myself.



Thanks again in advance, Rusty

 

[JLandry]

truck still broke

Rusty,



What do you mean by "broke"?



Are you talking about the violent shifting in and out of OD at 40 mph or something different?



John L.

 

[deadon]

Shifting in and outta gear at all cruising speeds. accelerating or decelerating it does fine.

 

[JLandry]

Shifting in and outta gear at all cruising speeds. accelerating or decelerating it does fine.

With those P0122 and P1682 trouble codes, without additional testing or info, they're pointing to a problem with:

• TPS (Throttle Position Sensor)
• Alternator
• A faulty PCM (Powertrain Control Module)

I'd suggest you start by cleaning and tightening all electrical grounds you can find under the hood, to include cleaning the battery terminals. If that doesn't help, I'd replace the alternator with a BRAND NEW one (not a rebuild). If that doesn't solve the problem, next I'd replace the TPS with a new one.

Worst case if a new alternator and/or TPS don't do anything, you've got spares!

Best regards,

John L.