2000 Rodeo Transmission stuck in Limp mode.

My tranny is stuck in limp mode. I can manually shift it, but it won't shift on it's own. The 'automatic' part of the automatic transimission is definitely not working right.

I searched and checked for the usual suspects, low battery or alternator output (measured over 14v at batt. when on), and the range selector switch. I removed the switch, took it apart, cleaned it up, and reinstalled it. It looked like it was in decent shape inside, although it appeared to have had a bit of oil of some sort that had leaked into it. There was a bit of oil on that side of the tranny, around the gear selector and switch, but not enough to actually drip as I don't have any stains on my driveway where I always park. The only thing I haven't checked is the atf fluid level, as I can't seem to find the my wrench that will take off the fill nut. I'll get that figured out tonight.

The tranny hasn't been taken care of like it should, I've had the fluid replaced two or three times over 100k of ownership, but I'm not sure about the filter. Would the need for a filter and fluid change cause it to go into limp mode? Any other suggestions of things to check? Also, it's not throwing any CEL codes either.

Thanks.

Where do I find the transmission control module on a 2000 rodeo? I've read to check the connectors and a few voltages at the TCM....

you should check the trans fluid, but...

limp mode is almost always a result of electrical/electronic problems, and *very* often the charging system, since the at electronic components and computer will not function outside a rather narrow range, either too low or too high <9, >16 volts.

computer location on the rodeo, i don't know but maybe could check a manual, but i'm sure a rodeo owner will chime in

//bc

Checked the fluid last night... It definitely needs changed based on the color. It seemed to be about a quarter to a half quart low as well. I pumped two quarts in and let the it continue to overflow some dirty oil out the fill hole until it stopped. I only had two quarts on hand so that was all I could do for now. Still in limp mode though.

Anything else I should check besides the TCU that I haven't found yet? Is it time to take it to the stealership? I usually take my car to a local shop (not a stealership) and they do a decent job on most things but is this something that they likely won't be able to debug or solve? Will I be better off taking it to the stealer?

you are confident that you've checked the charging system for sure? including the wires and connectors?

//bc

I wouldn't say I'm supremely confident... I've had problems with battery connector corrosion in the past, but last year I replaced the battery and the positive cable terminal. I removed both of the terminals, and cleaned the batt. posts and terminal insides. Tightened them both down good. Beyond that I haven't done much besides measure the voltage being over 14V when on and idling.

How do I do an alternator "under load" test? I'd like to measure the voltages at the TCM if I can find the thing. I have the 'shop manual' on CD somewhere that I'm sure will show me. I have to dig it out, it's packed somewhere as we're in the middle of moving.

Wife dropped the thing off with the 'local shop' today so we'll see what they have to say.

So the shop we took it to says my "transmission clutch" is out and it is slipping. I mentioned to them that it is in limp mode and it will act like that, and they said that if it was truely in limp mode then there would be CEL codes, and that it probably needs a transmission rebuild.

I don't know much about automatic transmission clutches, but on manual clutches, when they go, you can stomp it in any gear and feel it 'slip'. Wouldn't this do the same? When I shift to L, it doesn't seem to slip when I stomp it, or in 2-3...

So the shop we took it to says my "transmission clutch" is out and it is slipping. I mentioned to them that it is in limp mode and it will act like that, and they said that if it was truely in limp mode then there would be CEL codes, and that it probably needs a transmission rebuild.

I don't know much about automatic transmission clutches, but on manual clutches, when they go, you can stomp it in any gear and feel it 'slip'. Wouldn't this do the same? When I shift to L, it doesn't seem to slip when I stomp it, or in 2-3...first i'll say i'm not totally confident in diagnosing from this distance, and AT's can be tough anyway.
but...i can tell you that the AT limp mode will often not set a CEL.
and i *can* tell you, from what you have written, that the shop is full of it.
if it were a clutch, you would have the same problem with shifting it manually.
maybe it does need rebuilding, but i wouldn't go there anytime soon, and not from what you have written.
instead of chomping down on it in L Low to test for clutch slippage find a long incline and get it up to 3 third manually and then do it,.

i'm still betting you have an electrical problem. charging problem. alternator. or connectors. you didn't mention -- have you followed the battery ground wire to the body/frame, removed it, cleaned shiney bright and reinstalled?



//bc

Well... I'm still having problems... After driving the car around in limp mode for a few weeks (it's my only car) it started acting worse... it wouldn't shift up into '4th' gear anymore... it would jump around in gears... all strange stuff. I finally took it to a transmission shop and as I expected, they said the transmission needed rebuilt, torque converter or something. So.. a ton of money later, they tell me "the transmission is functioning properly and it shifts through all the gears when externally tested, but you have an electrical problem and it's stuck in low gear"!!!!!! They tell me that they have done their job and I need to come pick up the car and pay up. Not having any other option, I do it.. and take it a few blocks up the road to the Honda dealership who agreed to look at it for me. They call me today and say "Everything seems ok electrically, there must be something wrong inside the transmission"...

So... what do I do now? I can take it back to the transmission shop but I doubt they will be more helpful... perhaps I take it to one of their other shops to get a new perspective on the problem? The honda tech is writing up a report of what he did so when I take it back to the trans. shop they will know what has been tested.

To answer your question above, no.. I haven't followed the ground wire to the chassis and cleaned it up... I can still try that I guess when I get it back. Isn't there a list of points to measure voltage at, on the transmission computer, that tells you if you have a power problem? I've seen that list somewhere.... Where is the transmission computer anyway?

I hate to hear stories like this. I'm sure you searched and found many posters have gone through the same issue. Well, the issue being having tranny rebuilt and STILL having the same problem.

As many members will tell you, besides testing the voltage, they would have dropped the pan and visually checked the fluid and the filter. Perhaps throw in a partial fluid exchange at home.

I sincerely hope that your rebuild came with some sort of warranty. Go back to the shop and demand they stand behind their work. Was the work done at a chain shop?

You mentioned that the shop said something about the TC? Replacing a TC isnt that expensive compared to a rebuilding a tranny.

I know none of this helps you, but I would go back to the shop that rebuilt the tranny. Keeping going back until you get it done right.

I had my tranny rebuilt a year ago and it came with a 3yr/36,000 warranty.

**NOTE:
My tranny went into limp mode before it was rebuilt. Also, there weren't any CEL's, but I did have a stored code.

The rebuilt came with a 2 year 24k warranty and was done by that nationwide shop that Terry Bradshaw advertises for...... If it's electrical, I'm probably going to have to fix the darn thing myself... I'm an electrical engineer and I have the shop manual so I'll probably just have to print up all the wiring diagrams and schematics, and start probing until I find something that looks fishy... I just don't have the time to spend a weekend crawling under the car...

I've been emailing an isuzu tech who recommended that I start the car, then climb underneath and disconnect the position sensor, and try to drive it manually to see if it shifts. Disconnecting the position sensor will force it into "true" limp mode, and it should shift manually. If it doesn't shift, then something internal is wrong and the tranny shop needs to fix it. He also sent me the form to send off my PCM to have it reprogrammed if I suspect it's bad.

I'm wondering how the transmission shop verified that the transmission worked? They said "we hooked up to our tester and it shifts through all the gears properly" How exactly do they do that? What is an external tester? A dyno of some sort?

The only external test I am aware of is a test drive. It would cost them money to remove and tear open your tranny.

Most chain shops just test drive your vehicle to diagnose a problem. There's a reason most of us don't trust them.

They did drive it, they did open it up, and they did 'rebuild' it... I'm not sure what they replaced though...

my question is... they said after they rebuilt it that they tested it 'externally' and that it shifted through the gears.... does this mean that they hooked up power to the solenoids and tested that the solenoids worked? How else would they externally test it?

They did drive it, they did open it up, and they did 'rebuild' it... I'm not sure what they replaced though...

my question is... they said after they rebuilt it that they tested it 'externally' and that it shifted through the gears.... does this mean that they hooked up power to the solenoids and tested that the solenoids worked? How else would they externally test it?


Are you telling me that they removed your tranny and opened it up to diagnose the problem and then threw an estimate at you? Most shops don't drop the tranny during the "cost estimate" stage. I'm willing to bet all they did was test drive your truck and decided it needed to be rebuilt, UNLESS you saw the removed tranny. Why don't you ask the shop to give you a list of hard/soft parts they replaced and also ask how they tested it? All we're doing is speculating.

They drove it.. and supposedly hooked it up to their "trans check" machine, whatever that is.. and said something internal was wrong.. for $350 they would drop it and tear it open to diagnose the real problem... then they said my torque converter was shot and needed replaced, and it contaminated a bunch of stuff when it went out... so... a rebuild was done. They put it back together and now it won't shift... they said it's electrical and not their problem.. and that they did their job, which was to rebuild the tranny...

...a rebuild was done. They put it back together and now it won't shift... they said it's electrical and not their problem.. and that they did their job, which was to rebuild the tranny... yeah, i love that crap. their job, the one you paid for, was to correctly diagnose the problem and then to correctly fix the problem, which they haven't done, it would seem. time to ratchet up the noise....


//bc

I thought I'd post a follow up on this, since I hate reading threads that have no conclusion...

After I picked up the Rodeo from the transmission shop, I did my homework on the electrical system. I ohmed out every ground and power connection, and every input and output of the transmission. Everything seemed OK. The only few signals I didn't check were switching signals which wouldn't give me a valuable reading on an ohm meter. I checked all the fuses as well and replace one blown fuse. I don't recall which fuse it was, but it was on the fuse box under the drivers seat, 30A, and on the 'left' column. I only had a spare 20A, but it seemed to be doing it's job and didn't blow right away.

After checking all the electrical, I decided it was time to take it back to the tranny shop. Not only was it not shifting but it was leaking tranny oil terribly so they had to fix that anyway.

While it was initially just stuck in 1st gear after picking it up, it seemed to start shifting properly after about 15 minutes of driving. And by properly, I mean like a tranny stuck in limp mode should shift. This doesn't seem relevant to my problem but I thought I'd add it in here briefly in case someone else runs into it.

The tranny shop this time says that they are getting proper CEL codes that might lead to a conclusion. Before we weren't getting any. The only thing I changed was the blown fuse. I don't recall the CEL number, but it was for a bad vehicle speed sensor.

I did some research on the CEL and found that either a failure of the VSS, or the transmission speed sensor, which is on top of the tranny, will give this same CEL code. Because my speedo was still working properly I suspected the TSS. I told the trany shop that the TSS would cause the same thing, and asked if they had checked it, to which they replied "yes, of course". So, I pick up the car again and figure either a new TSS or VSS will fix the car, and since the TSS was cheaper, and I was leaning that way anyway, I bought the part.

So I tear out my console, and remove my 4WD shifter boot to get to the tranny and what do I find??? The darned tranny shop did NOT connect the TSS. Not only did they not connect it, they broke the latch off of the connector. I plug it in, clear the codes, and take it for a spin... All is good!

Now.. obviously I can take it back to the shop and get nasty with them but honestly, I'd just rather move on with my life and be happy... so I just used a zip tie to secure the connector, and buttoned it all back up.

So.. in short, I probably did need a new transmission, but the tranny shop introduced a different problem that had the exact same symptom.

There is a small possibility that the TSS latch was already broken, and that the TSS had vibrated loose, and that was the issue all along. It's doubtful though since we never had a CEL for that. And the tranny shop had to remove the tranny to rebuild it. I'm also curious to know if I fixed the reporting of CEL's by replacing that fuse, or if I had some sort of loose connection or wiring harness issue that I 'fixed' by all of my pulling and probing.

I'm glad to have it back on the road though after six months of sitting. A million thanks goes out to Jerry L who answered hundreds of questions and helped me debug the issue via email along the way and for providing me parts at a great price.

Wow. Thanks a lot for posting that update. I lost the torque converter lock up by tugging on the tranny harness to fix an O2 wiring problem several months back. The auto tranny doesn't like electrical problems, does it? Glad you got it resolved and hope the rebuild lasts a LONG time!

My 2002 Isuzu Rodeo with the 3.2L V6 downshifted from 4th to 2nd on the highway at about 65 miles an hour to pass and not it is stuck in what I think is "limp mode". The transmission will shift from Park to Reverse and then into Neutral fine and engage the gears. When I shift into Drive the vehicle will not shift higher than 2nd. Also, the dash indicator will only show Park and 2nd. Nothing in between. I have changed the transmission fluid and filter. There was not any large particles in the fluid although it was pretty dark, and had a burnt odor to it. I have checked all of the connections to the sensors to make sure they are plugged in correctly. I also have checked the battery and alternator. The battery sustains about 12.7 volts and the alternator puts out a steady 14.2 volts. Please someone who has any ideas please help. This is my only vehicle so I have to keep driving it to work.

sounds like you need to clean or need a new range sensor :


http://www.walkerdowney.com/ryanendres//isuzu/#faq59

So one of the connections inside of the range sensor was broken. Now I am working on finding a new one and hopefully it will fix the problem.

That should probably fix it ... I know when mine finally went the dash indicator lights were messed up and it was slamming in and out of gears ... I just drove it directly to my dealer about 3 miles away and had them swap out the part ...

a new range sensor/neutral safety switch fixed all of the transmission problems I was having. It even fixed the shift points so I am not reving out quite so much. Thank you for all of your help.

So I was driving to get dinner tonight and my Isuzu dropped into limp mode again. Guess it is back to the drawing board again. Hopefully my Brand New Range Sensor is still in one piece. I think I am going to start tracing wires to see if any are grounding out.

So after tracing every wire I can until it goes between the back of the engine and firewall with not finding any broken wires, tearing apart my entire dash and reconnecting any plugs I found, and even replacing all of the fuses the Rodeo is still in Limp Mode. I have looked inside of the new Range Selector and nothing is broken. I have disconnected all of the sensors on the transmission and reconnected them after cleaning the connections with electrical cleaner. I still do not have any drive gear higher than 2nd, and park on the dash. With manually shifting I can get it into P, R, N, and 2nd.

I am completely out of ideas short of junking the truck. There is not a shop around here that will even look at it for less than $1000 that I can drive to. The nearest shop that will even look at is with a decent reputation is 1 1/2 hours away at 75 MPH. Does anyone have any ideas. I have been looking for the TCM and starting to think that I do not have one. There is nothing under the dash, under the center console, or anywhere near the Transmission underneath the Rodeo.

Try posting this on planetisuzoo.com

a lot more active site ...

My Isuzu Rodeo 2000 3.2L V6, have a automatic transmission. The problem is when I put in D, the indicator in the dash put reverse and the car goes reverse. The other problem is i can't put in parking. Whats wrong with my car, someone helps me... How can I fix this?