TRANSMISSION IN ??LIMP?? MODE

2001 DODGE CARAVAN
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BOBSCNC
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Transmission problem
2001 Dodge Caravan Two Wheel Drive Automatic 101187 miles

The symptons are: When you turn key onand it does the little thing to check all dash lights. it gets to the point where it turns all the boxes around the P R N D etc. they should go out but all the boxes stay lite.
Rev and one of the FWD gears work but it does not shift up or down. The speedometer and odeometer do not move or change. Tach and all other gauge seem to work OK. the dealer I bought it from did a diagnostic scan. It returned something about the data link was bad to transmission.



Another mechanic said that the output speed sensor was the problem. Changed that NO HELP.
He suggested the input speed sensor next. Changed that NO DIFFERENCE.

I am at wits end here.

some thing to add: I noticed that the check engine light WAS NOT on when I test drove it after changing sensor I have a $15 donation from another unrelated elect problem. That turned out to be a weak 40A circiuit breaker just for info.
Apr 8, 2009 at 11:46 AM
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BMRFIXIT
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locate TCM and check wiring harness
check yellow wire for power when key on or engine running
the TCM is located behind the inner

fender well of the driver side wheel. It has a very high failure rate due to corrosion
check wiring harness
let me know
Aug 18, 2017 at 8:17 PM
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BOBSCNC
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I found the the input shaft speed sensor to be bad thanks for this post cost me $43.00 to fix it.
Aug 18, 2017 at 8:18 PM
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BOBSCNC
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I removed the connector from theTCM checked the yellow wire, there is 0 Volts present with the key in run position.
Aug 18, 2017 at 8:18 PM
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BMRFIXIT
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check fuses
check for a short in the wire
go back about a foot and check for power
Aug 18, 2017 at 8:18 PM
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BOBSCNC
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Where does this Yellow wire go to from the TCM? What is the next place it connects to something?


All fuses are good.
Aug 18, 2017 at 8:18 PM
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BMRFIXIT
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Fuse box than ignition switch


https://www.2carpros.com/forum/automotive_pictures/99387_Graphic1_298.jpg


https://www.2carpros.com/forum/automotive_pictures/99387_Untitledtt_1.jpg

Aug 18, 2017 at 8:18 PM
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BOBSCNC
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thanks for the responce. I will track and check the wire in a couple of hours. It is only 30 DEG out side.
Aug 18, 2017 at 8:18 PM
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BMRFIXIT
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make sure you check the wire under the fender and under the fuse box
Aug 18, 2017 at 8:18 PM
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BOBSCNC
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Here it is 4 PM central time In wisconsin.

I was tracking the yellow Wir with out much success.

I studied the schematics again and came to some conclusions.

Not trying to start a disagreement but here are some of my thoughts / questions.

I am useing Mitchel schematics from Eautorepair.com which apears to be the ones you use.

Looking a t schematic POWER DISTRIBUTION CIRCUIT (2OF 3) from mitchel,
and doing a test of the ignition switch
The Yellow wire is only hot (energized) when the switch is in the 'START' position. The pink/white wire is hot in the run position.
some of the schematics show a connection between the run and start connection but I think that is only there with the key in the start position and not in the run position.

are we sure that we want to be chasing the yellow wire.
I have the front tire and splash panel back on If the eweather is nice I whill pull it back off andt check the yellow and the pink and white.

Have a good easter and will catch you later.

Bob
Aug 18, 2017 at 8:18 PM
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BMRFIXIT
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happy easter to you too and to all

so many wires and so many colors
Yellow and red wire should have power at all time
yellow should have power with key on and starting
if not very common for a harness to fail under the fender or around the fuse box
if all ok suspect bad TCM

good luck
let me know monday
Aug 18, 2017 at 8:18 PM
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OBXAUTOMEDIC
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Hello,

I have found that 9 out of 10 times with Dodge it is the TCM. The last Dodge with your symptoms that I worked on it ended up being either the Input or the Output Sensors, I say that because I usually just replace both since they are so inexpensive and pretty easy to change, and that fixed the problem. And since you have already change them I would say that it is your TCM.

.
Aug 18, 2017 at 8:18 PM
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BOBSCNC
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any Idea of what they cost?

Have to check scrap yards and look for one that has been rear ended.

Bob
Aug 18, 2017 at 8:18 PM
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OBXAUTOMEDIC
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[quote:18e261a028="BOBSCNC"]any Idea of what they cost?

Have to check scrap yards and look for one that has been rear ended.

Bob[/quote:18e261a028]

Hi Bob.

Here in my area I have been able to get them for around $250 from the dealer.


.
Aug 18, 2017 at 8:18 PM
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BOBSCNC
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From tests on the the wires I believe it is the TCM also.

I have read somewhere or heard from some one that if I change the TCM The speedometer has to be recalibrated and possible some other things done with the computer?

Can you fill me in on that?
Aug 18, 2017 at 8:18 PM
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OBXAUTOMEDIC
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[quote:8b8d62e967="BOBSCNC"]From tests on the the wires I believe it is the TCM also.

I have read somewhere or heard from some one that if I change the TCM The speedometer has to be recalibrated and possible some other things done with the computer?

Can you fill me in on that?[/quote:8b8d62e967]

I don't think the Speedometer will need recalibrating, the only thing is you will need to have the dealer program the TCM.


.
Aug 18, 2017 at 8:18 PM
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BOBSCNC
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I just installed a different TCM. It failed the power on diagnostic just like the other one. ( what happens is when the key is turned on and all the inst cluster lights come on and off but all the boxes around the gear position letters stay on.

So I no longer think that the TCM is the problem.

I have discoverd something new. The ASD relay is clicking of and on at a rapid pace. I think that ASD stands for Auto Shut Down. Is that correct?

It is very quite. I was going to put the starter relay in the IPM, I happened to feel a vibration and when I listened I could hear it.

I am checking the schematics but in the mean time maybe you might know if or how the ASD relay could figure into this

Bob
Aug 18, 2017 at 8:18 PM
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BMRFIXIT
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wiring wirng wiring
check it out
I am all against replacing parts with out checking 1st
Need a tool or a tester CHECK IT @
https://www.2carpros.com/affiliate/uid/bmrfixit_1
need manual CHECK IT @
https://www.2carpros.com/kpages/auto_repair_manuals.htm
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Aug 18, 2017 at 8:18 PM
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LSOTO
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I"m getting aP1684 and the evil P0700 codes only. I retrieved the codes from the ignition turning method. I'm not too concerned about the 1684 code. My concern is the p0700 code. I have only replaced the input speed sensor- nothing. The strange part is the limp mode is on-off. I can go to work with the mode on, then return without the mode. I can let the van sit for a day or two-- no mode-- go somewhere turn the engine off-- mode is on. I'm thinking the TCM is bad or could this be a wiring issue or output sensor issue. I'm low on funds so I'm trying to avoid repair shops.
Jun 26, 2020 at 1:01 PM (Merged)
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CH112063
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You've replaced the input sensor, and your not sure of the next move and no money to repair. I certainly understand your dilema. Why not do this, check the fluid, and if its clean, and is not burnt, you may find a shop thay can scan just the transmission Control Module, some auto stores and repair shops have a scanner that can do this. I believe you have scanned the powertrain module, the TCM has its own codes. It may just need servicing, a fuse could be out. Why not read up on this problem on the website. It explains everthing. Plus they have all the information regarding checking out all the things you may need. There are many reasons for limp-in. I would try to make sure the fluids ok first, the check the trans codes. Your PCM is telling you what you already know. Does it ever not drop into limp in? Does it have 3rd speed in 'D' or the other forward selrctions? Other than OD.?
Jun 26, 2020 at 1:01 PM (Merged)
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LSOTO
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Thanks for the reply...it has done a limp-in mode before while driving but mostly on starting the van. I do get 3rd gear in which all appears fine but the code is still there. This week all the codes did clear out only to return. I was clearing the codes by removing the pos and neg battery which had limited results in clearing the limp-on
I've been looking around this site for repair tips. I did go to a tran shop today. I think it was BS. After doing a basic check, they said replace TCM. This is without having done a full diagnois which they wanted $85 to do the full diagnois.
Looks like I might have to go to the dealership and pay for a full diagnois.
Jun 26, 2020 at 1:01 PM (Merged)
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CH112063
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Your a pretty sharp fellow. Not only will they give you the proper attention, they have the proper means to flash the TCM. And the correct parts. If you've checked both fuse boxes, and checked the frluid thats the best thing. After you find a good dealer, any Chrsler dealer can do this, get their diagnosis, and if you need advice let me know. Thanks for the reply. Phone around, ask them if they have an ASE certified man doing trans. work. They should say yes. With no hesitation. If they stumble their answer, keep looking. ok, your welcome. Thank 2carpros, their the people with the vision. Good luck sir.
Jun 26, 2020 at 1:01 PM (Merged)
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LSOTO
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Update... Paid to have a full check. The mech. said bad TCM. The van is still on-off mode. This makes me wonder if that "is" the problem.
Jun 26, 2020 at 1:01 PM (Merged)
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CHAZ_S1
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Hi,
The only code it pops is P0605. I have cleared it and it re-appears immediately. I have checked continuity on all 31 wires of the tcm to the corresponding connectors.

What sequence of voltage checks should I make next? Engine running or ignition on, in gear or park?

Thank you
Chaz_s1
Jun 26, 2020 at 1:01 PM (Merged)
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BMRFIXIT
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This DTC will set if an internal TCM malfunction occurs

Check all pin and make sure none is pushed out
check fuses and relay with key on engine on and or running

record all DTCs and erase codes
turn ignition on and then start
move the gearshift lever slowly through each gear position
if DTC return ,replace TCM
Jun 26, 2020 at 1:01 PM (Merged)
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CH112063
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The scanner is the whole thing because at the dealer, there were 6 or 7 re-programming bulletins, a larger computer would clear the TCM, and that would fix many shift complaints. So it may be the TCM. There's a part number on it. If you can call a dealer parts department, they can tell you if your part number supercedes to a revised(fixed) TCM software program for shifting. It may be the TCM internally. 2001 had a new design electrically, drove technicians to re-flashing(reprogramming) it. I hope it works out for you.
Jun 26, 2020 at 1:01 PM (Merged)
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CHAZ_S1
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Hi,
Thanx for the reply! I have checked volt.s
I have swapped out relay with identical working relay
All fuses ok.
I have 13.6 when eng. running on Yellow/red(pin56)to tcm

There is no voltage from tcm(pin16)or(pin17) back to relay and sol. switch yellow/org

There is no voltage from relay to tcm(pin15) yellow/brn

I do get a small variable voltage as the ign switch is turned to start, but goes away
My meter shows neg. polarity when put in gear on the 3 wires mentioned above and back to pos. polarity in park

Only P0605 shows
Jun 26, 2020 at 1:01 PM (Merged)
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LSOTO
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update to the update...with the help of Santa's dollars I was able to replace the TCM. I'm happy to say all is well so far!!! I was getting quotes of $480 -525.00. I checked with Auto Compter Exchange.com for a remanufactured TCM which they claim is plug-and-play. The part cost $150.00 with free shipping.
Thanks to this form and writers for your help.
Jun 26, 2020 at 1:01 PM (Merged)
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BMRFIXIT
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https://www.2carpros.com/forum/automotive_pictures/99387_Graphic1_506.jpg


https://www.2carpros.com/forum/automotive_pictures/99387_Graphic2_245.jpg

Jun 26, 2020 at 1:01 PM (Merged)
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CH112063
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That's a very reasonable price, and I am happy for ya.
Soon, you'll be able to just plug both power and software updates into each car so its warm, and starts and runs good, it will let you know by mileage each services it needs, make the appointment and pay for it in advance, I hope, especially the pay for it part, see-ya
Jun 26, 2020 at 1:01 PM (Merged)
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BMRFIXIT
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https://www.2carpros.com/forum/automotive_pictures/99387_Graphic1_506.jpg


https://www.2carpros.com/forum/automotive_pictures/99387_Graphic2_245.jpg

Jun 26, 2020 at 1:01 PM (Merged)
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CHAZ_S1
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Thanx for the diagram, I can't view it. The size and resolution are too low.

With no voltage out to relay, and all wiring, connectors, and fuses appearing good. What could I look for next?
Jun 26, 2020 at 1:01 PM (Merged)
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BMRFIXIT
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bad TCM
Jun 26, 2020 at 1:01 PM (Merged)
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CHAZ_S1
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Hi,

Thanx for the insights, it WAS a failed TCM...I replaced it and now runs fine...so thank you all at 2CARPROS!!!!
Jun 26, 2020 at 1:01 PM (Merged)
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NALLEN524
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I have a 2000 Dodge Grand Caravan 3.8L 146k miles.

It shifts ok when I first turn it on but shifts at wierd rpms. But when the engine/transmission warms up, its in Limp Mode and wont get out of 1st gear.

Could it be the input and/or the output speed senors? Or a vacuum hose? please help!!!!!!!!!!!!!!!!!
Jun 26, 2020 at 1:01 PM (Merged)
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BMRFIXIT
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https://www.2carpros.com/forum/automotive_pictures/99387_Graphic9_36.jpg

Need to check for codes suspect tranny solenoid pack and or speed sensors good luck
Jun 26, 2020 at 1:01 PM (Merged)