2002 Town and Country - automatic transmission shifting problem

[zukdj]

PO123, TPS (Throttle Position Sensor), apparently since the sensor isn't working it can't tell the van when to shift properly since it isn't seeing the throttle open. The part was $40, I'm going to put it in this weekend. I'll report back with my findings. BTW, I was told this part seldom throws a code so if your seeing these symptoms this may be your issue as well. You have to remove the throttle body to replace the sensor. Anyone else ever replace a TPS?

[zukdj]

Much better, the TPS seemed to do the trick for me. The part was $40 and was fairly easy to install. While you have the throttle body off you should probably clean it good with some Gumout, replace the air cleaner at the same time. WOW, what a difference, no more bucking or tranny problems.

[allenprimo913]

does it apply to older vans too? i have a 1998 ply voyager and it jerks a lilttle right after 2nd gear shift but runs fine above that then it jerks again when you slows down to a stop. i did almost everything all i can think of to do. i replaced tranny fluid & filter, replaced busted tranny mount on the front, adjsuted shifter cable, repaired leay tranny hose and replaced both input & output sensors.

the jerking is less but i still feel it once in a while both after take off then when you come to a stop.

i got no code , how much did you pay to get those tranny codes?

thanks

[allenprimo913]

any replies guys

tnks

[jreodica]

I've got a 2002 T&C FWD 3.8L...

Sometimes I would get "bucking" between 1st and 2nd gear.

More recently, the van would not shift between 3rd and 4th gear! Plus the Check Engine light was also on. I thought this meant I'd have to drop a few thousand dollars for the transmission to get fixed.

But I came across this thread and found my solution!

The ERROR CODE I was getting was "P0700" without using any readers - just by using the van keys, ignition/diagnostics process - OFF/ON x 4 and the error code gets displayed on the digital Odometer.

(P0700 = Transmission Control System circuit failure)

It turned out to be a faulty Throttle Position Sensor. It was only a $36 CND part that I bought at Part Source here in Canada!

It took me about 1.5 hours to fix by following these steps:

1. Disconnect the negative battery cable from the terminal. Remove the hose clamp from the air inlet-to-throttle body. Take off the two mounting screws and remove the air inlet resonator.
2. Step 2
   Remove the throttle as well as the speed control cables from the lever and the bracket. Disconnect the electrical connectors from the idle air control (IAC) motor and the throttle position sensor (TPS).
3. Step 3
   Take the vacuum hoses from the throttle body. Loosen and remove the mounting nuts that hold the throttle body in place.
4. Step 4
   Lift out the throttle body assembly and the mounting gasket. Place a clean shop cloth over the manifold to prevent debris from falling into it. Unscrew the old TPS (Throttle Body Sensor) and remove the small seal so you can re-use it on the new TPS. Screw the new TPS to the throttle body. Spray electrical contact cleaner on all electrical contacts before plugging everything back in.
5. Step 5
   Set the throttle body with a new gasket on the intake manifold. Place the mounting nuts in position. Torque the the nuts to 18 foot pounds.
6. Step 6
   Reconnect the vacuum hoses to the throttle body. Reattach the IAC motor and the TPS electrical connections to the throttle body, then connect the throttle and speed control cables.
7. Step 7
   Place the air cleaner/inlet resonator assembly in position. Reconnect the negative battery cable. Start the engine and check for proper operation.

Thanks for the help guys!

[Alphabravo]

WOW! How did you come up with a bad TPS from that code? I'd have never thought about a TPS. The same P0700 code popped up on my 97 GV 3.3L today. I hope it doesn't send me on a witch hunt.

[icebox114]

mark t&c tranny problems

[Bigbuckjohn]

My Daughter's 2000 Grand Caravan had s similar problem. I read all this posting and followed it. I changed out the speed sensors ($17 each at Auto Zone) but that didn't help. I found out someone who was messing with my daughters car had pulled the fuse for the ATX relay(or AVG)? something like that since the car is not here I can't double check it. I replaced the 20 amp fuse and it worked just fine. Thanks to all of you who responded to this thread. It helped me find the speed sensors and they were very easy to replace.

[treglassman]

I am new to this forum and hoping to find some answers regarding my 2000 town and country. I was wondering if replacing this TPS sensor would help with my limp mode tranny problem. I went to auto shop yesterday and got some codes. P1790, PO733 and P1792. He told me it was internal, but i dont believe it. I have already replaced the input and output sensors and the selenoid pack and also changed filter and fluid (atf4). The van has been giving me a hard time starting also. Tranny was running fine and all of a sudden it made a whineing noise and lost power. Pulled over to the side of road, turned off and then restarted. I could only do about 30-35 mph with rpm around 3. made it home and started to do some research. I replaced items according to other forum info. But van still has the problem. Any advise would be appreciated.

[RIP]

Originally Posted by treglassman

I am new to this forum and hoping to find some answers regarding my 2000 town and country. I was wondering if replacing this TPS sensor would help with my limp mode tranny problem. I went to auto shop yesterday and got some codes. P1790, PO733 and P1792. He told me it was internal, but i dont believe it. I have already replaced the input and output sensors and the selenoid pack and also changed filter and fluid (atf4). The van has been giving me a hard time starting also. Tranny was running fine and all of a sudden it made a whineing noise and lost power. Pulled over to the side of road, turned off and then restarted. I could only do about 30-35 mph with rpm around 3. made it home and started to do some research. I replaced items according to other forum info. But van still has the problem. Any advise would be appreciated.

It appears the computer detected a fault code and put the transmission into what's called "limp mode". This limits you to 1st, 2nd, and reverse gears to decrease the chances of further damage. Of the three codes only the P0733 (A/T Additional Gear Ratio Error In Third Gear) will trigger limp mode. The P0733 code could be caused by a data mismatch between the input and output speed sensors or a slipping or worn internal UD clutch.
The P1792 code indicates a power interruption, maybe a battery disconnected and the P1790 code indicates this:

"P1790(36) -Fault Immediately After Shift When monitored. This code is set if the associated gear ratio code is stored within 1.3 seconds after a shift. This code will only be stored along with a 50 (gear ratio) series code. If this code is set, it indicates the problem is mechanical in nature. When this code exists, diagnosing the transmission should be based on the associated gear ratio code and primarily mechanical causes should be considered."

Could have them check the Clutch Volume Index (CVI) numbers for the UD clutch. Out of range numbers will mean a rebuild.

[treglassman]

Thanks!! I will bring it to the shop tomorrow and get more details. I will let you all know my fix. Question: what would cause a data mismatch with the sensors and is there anything true about the wire splices and ground strap?