Voyager Tranny "Limp Mode" P0715

On my way to my Inlaws this Easter weekend, my 01 Voyager turned on the Check Engine light, and then went into Limp Mode on the Turnpike. I bought a ODB-II tool at the closest Sears, and I had 3 codes: P0715 and two P0700s. The P0715 is an "input turbine speed sensor circuit failure". The P0700 codes are just telling me that the main computer got an error from the transmision computer.

I cleared the codes, and kept going. It was 8PM on the night before Easter, so no chance of getting anone to look at it until Monday. The Check Engine came back on about 10 miles later. Another 10 miles, and the limp mode came back on. I learned that I can get out of Limp mode by pulling over and turning off the engine.

For those who don't know, the 41th tranny on all 6 Cylinder Mopar Minivans is computer controlled. If the computer doesn't like the information it is getting from one or more sesnors, it goes into "Limp mode" (forces the tranny into 2nd gear). You can get home, but the engine screams at 4000+ RPM on the highway.

I got around on Easter by puilling over and shutting off the engine, and Ocasionally clearing the codes. Monday, I drove 90 miles back home, with no check engine light or Limp mode. I checked for codes when I got home, and I have one P0700 and one P0715.

I have had no problems with this van shifting at all. This problem started real suddenly, after My 5 year old ran the battery down playing in the van for a few hours.

Can some one guide me:

1) Should I replace the sensor, how expensive is it, can I get it at Pep boys?, how often do they fail intermitantly, where is it?
2) I have heard of ground strap issues causing Limp Mode... Which strap + where is it?
3) Would the Dealer get more information with the $6000 DRB-III tool that they have, and would it be worth trying?
4) I had sears check the charging system + Battery, and it is 100% (I bought the ODB-II tool while I was waiting). Anybody think there is a relationship between the dead battery, and the begining of the Limp Mode symptoms?

replace the input speed sensor and you should be alright.easy to do ,just unplug it and then unscrews from the tranny. about 25 from Advance auto

I can't locate any info on this part, I suggest you buy a repair manual and try to find the location and replace it if possible. Sounds like your 5 year old burnt it up.

Earlyrizr is right, it's at Advance Auto. I was looking at Autozone, they didn't seem to have it.

Now that I am home, I have access to my Factory manual on CD. I managed to locate where the sensor is. It wasn't too hard to find the sensor in the manual. Trying to match the crude drawing in the manual to the actual transmission installed in the van was a real pain in the butt.

Note that this part is not the "vehical speed sensor". The sensor that posts the P0715 gets its pulses from a large ring gear on the back of the Torque Converter. The TCM sontiniously checks the ratio between the input sensor and the output sensor, looking for slippage and the quality of the shifts. You lose the signal, the TCM assumes it should go LIMP. They should have two sensors, so they can tell the differance between a sensor failure, and a real problem.

A bad ground could cause a loss of signal as could a loose conector. The connector looks fine.

My usual source, MoparPartz.com (sells direct from chrysler) does not offer the part on thier web site, so I would be surprised if Advance Auto has it. I would think it would be specail order from the dealer.

I don't know if this is related: A few weeks ago, my speedometer went nuts as I started the car. It bounced back and forth, peg to peg several times, until it got stuck on the wrong side of the peg next to zero MPH. Driving without a speedometer is really strange.

This "wrong side of the peg" thing happened once before just as I was leaving on a long trip, but fixed itself when we got to our destination. I had to replace the battery on that trip, and I wonder if a low battery situation is related in any way.

You're in luck, Earlyrizr is correct. Advance Auto has BOTH the TSS and the VSS. Your's is the TSS. You have a choice of $16.99 or $24.99. See here:

http://www.partsamerica.com/ProductList.aspx?PartType=1179&PTSet=A&SearchFor=Speed+Sensor

:icon16: Will sombody smack me with a wet mackerel. It looks like the right part is at Autozone. It is "GP Sorensen Speed Sensor, part# 7799701" It costs $24.94.

Note that I had to enter my van as a Dodge Caravan, and not a Chrysler Voyager, to find it. :banghead:

Well I bought the sensor on Tuesday, and Tuesday night, I went to change it. I ran the scanner on it, and there were no codes! I have checked every day since then, and no DTC's were stored.

I decided not to fix what at the moment ain't broke, and I threw the sensor into the glovebox. I wonder if the extremely low battery voltage right before the problem apopeared caused the TCM to get really confused.