****** woes... Need ideas!

[tinyejp]

Alright, fellows. Long time lurker, first time poster.

I've laid my hands on an 03 Liberty Limited. Pretty nice ride, but it has a major flaw, which let me snap it up pretty cheap. It's an early 03, but it had the 42rle. Confirmed with the build sheet. Here is the story:

The fellow I got it from bought it with a known ****** issue, and was told it needed to be replaced. He did so, and the mechanic called and told him the replacement was no good. It was removed, and he took it back to the scrapyard for an exchange. The second replacement was installed, and deemed no good by the mechanic. When asked what the problem was, it was the same issue it went to the shop with... BOTH TIMES. Can we say hack?

After the guy made him pay for the install TWICE, he took the jeep, drove home, and put it on Craigslist. I called him four hours later and the rest is history.

So, the problem is that it is in limp mode. It is throwing a p0720, which indicates the output speed sensor. The guy replaced it and the pigtail, and did some wiring "repair" as the loom had fallen onto the front driveshaft and got chewed up. He used quick connects (which I do not trust), so I replaced those the first day.

Solder and shrink tube those wires. Nope, still throwing the code. Switch the wires thinking maybe he got them backwards. Nope. Replace the TCM with another that has the same part number. Nope.

I ordered a Mopar output speed sensor, but it got lost in the mail Monday and hasn't turned up yet. The one that he used was from a parts house, so it is suspect right off the bat. That and the wiring from the TCM to the sensor are all I can think of that is left in the system. Sometimes it throws a p0731, but I think that is a symptom rather than a problem.

What am I overlooking here? Should I run a wire from the pigtail up to the tcm? What tests can I run to see if the wiring is good? Should I have a certain voltage or resistance on either of those wires? Do those wires go anywhere besides the TCM? It doesn't look like it to me from the wiring diagram, but maybe someone knows something I don't.

Any help would be great, fellas. I've learned a lot here already, and I thank you all for that. Here's hoping someone can do it one more time!

 

[tinyejp]

Another thing occurred to me. Can someone with this ****** combo take a look at the speed sensors and let me know what the wire colors are? The wires on mine do not match the wiring diagram in the FSM. I have a Black/Blue stripe on both, which is correct. The input has L. Green/ White on the signal side, and the Output has Tan(or maybe Brown?)/White. The FSM shows it should be Red/Black on the input and L. Green/White on the output.

Swapping them doesn't change things much, although it takes away the P0720 and only throws the P0731 consistently...

I wonder if the hack mechanic botched the wiring, and the Red/Black is hiding somewhere else...

 

[nullptr]

Can't help you, sadly, but it does sound like you're looking in the right places. Best of luck!

 

[libertybob]

'03 Liberty

I have a '03 liberty with 42rle trans. '03's used 45rfe trans up to Feb 26 2003 so your build date on the door should be after that date. My build date is June 2003. If you have a wiring diagram, why not go to the TCM plugs and find the wires that go to the output sensor and check continuity from the plug to the sensor. I don't know if the wiring changed when the switch was made to the 42rle trans. If it did, the wiring diagram might not apply to the 42rle. If you can't figure it out on the wiring diagram I can check my wiring color for you so let me know. Also make sure the correct input and output sensors are being used. Either the 45rfe or the 42rle uses a different output sensor than the input sensor. One of these two trans uses the same sensor for both input and output but don't remember which. It is something to check however. I am using inexpensive input/output sensors bought on eBay and they work fine so I suspect your trouble may lie in the wiring. Keep us posted. PS: Investigate whether the TCM you swapped out with your original TCM for test needs to be flashed to your VIN number to operate properly. Don't know if it must be flashed to your VIN but this is something else to check.

 

[tinyejp]

Thanks guys. This one was built in February or March, I can't recall at the moment. I contacted Chrysler and got a build sheet, and the 42rle is what came in it from the factory. The 45 uses the same two sensors, and the 42 uses two different ones. I agree that the wiring diagram I have may not be accurate. If you could check your wire colors, that would definitely help! Maybe I can find a later diagram. How long did they continue to use a separate TCM with the 42?

I wonder also if the TCM needs to be flashed or not. I suspect the original should be fine, though I am not certain the one that came in it IS the original. There's no way of telling if someone swapped it before it came to me. The part number is correct for the year and ******, but I know no more than that.

 

[tinyejp]

Ok, the lost sensor arrived today.

Still no good. The codes changed, though. The first run gave me a P0733! 3rd gear ratio incorrect. It never went into third gear! I swapped back to the original TCM at this point, considering what we discussed earlier. The second run gave me a P0731. I swapped the sensor connectors at this point, and cleared the codes again. Third run gave me a P0732! Second gear ratio incorrect! What the heck is going on here?!?

The only good news is the P0720 never came back. That aftermarket sensor may have been bad after all. Small consolation.

Here is my plan of attack: I need to know the wire colors for the sensors, input and output. I also need to know which side of the connector in relation to the retaining clip the wires go on, but only on the connector that does not have the green/white and black/blue wires. On mine, that is the tan/white and black/blue pair, but something tells me that might be wrong... I found a pinout for the TCM plug today, and I plan to look it over later on if I get time. My concern is that the fella may have switched the wires when he put on the new pigtail.

Right now it's time to take the kiddies to their extracurricular activities.

 

[tinyejp]

ok, I couldn't resist. Checked the plug against the pinout. The plug is correct everywhere. Red/black where it should be headed to the INPUT. Green/white where it should be, headed to the OUTPUT. The wiring at the sensors HAS to be wrong! ...or someone spliced in another chunk of wire at some point. Either way, it looks like I'm running some new wires.

 

[tinyejp]

FIXED!

Ran a new wire from the TCM connector down to the connector where the splice was. Then swapped the connectors so they were in the proper order. Runs and drives like a champ now! Hooray!

Now I just need to figure out why the drivetrain is so noisy. Need to change all the fluids and such, and check out these tires that are on it. I've never heard of them, and they could be a good portion of the noise.

 

[tinyejp]

Thanks everyone for your ideas and support!

 

[libertybob]

Yippee!

Congratulations! Patience and perseverance trumps ignorance every time.

 

[uss2defiant]

Great job!!