2003 Jeep Wrangler Limp Mode (42RLE)

cvettori55

cvettori55

Jeep Noobie
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Sep 16, 2019
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25
Location
Illinois
My buddy left for College mid way through putting his jeep back together. So it ended up with me. I Just got it running a couple of days ago. Fresh battery as well.

Issue: Jeeps stuck in second gear and can't shift it manually either. The real reason I'm posting this is because the resource I rely on for most of the code descriptors and probable causes is prodemand & there is zero information regarding the 3 TCM codes that are currently stored. The ECU codes I'll I'll able to work out. It's transmission issue I'm currently concerned about.

Codes: TCM - B0054, C0057, P0036. ECU - P0301, P0700, P1492, P0031
 
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I didn't look up any other codes but the limp home means the transmission really isn't happy, that's why it's stuck in second gear. The P0700 is a generic code, you need a better code reader to see what's really wrong with the transmission. Generally with a whole slew of codes I'd check your battery cables and ground cables really carefully to be sure they are perfect, free from corrosion or damage of any kind. The computer needs good grounds to operate.
 
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pagrey said:
I didn't look up any other codes but the limp home means the transmission really isn't happy, that's why it's stuck in second gear. The P0700 is a generic code, you need a better code reader to see what's really wrong with the transmission. Generally with a whole slew of codes I'd check your battery cables and ground cables really carefully to be sure they are perfect, free from corrosion or damage of any kind. The computer needs good grounds to operate.
Click to expand...
First 3 codes are stored in TCM
 
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Talked with one of my instructors and he said that the codes I got off the scan tool may not be proper. I have access to the Chrysler factory scan tool at my school and I'll attempt to limp it there see how that goes
 
That's what I'd do. If it's really broken driving it isn't going to do much more damage, it'll need to be fully rebuilt anyway. Before you drive it you might add one quart of ATF+4 to the thing. Running a quart high is fine in that transmission and if you are low it might help. If you've got an instructor with the tool I'd bet you'll get good advice.
 
cvettori55 said:
We will see how it goes. Crazy how you just let things sit and everything goes to hell
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That is no understatement. I got a 2003 Rubi with 20,500
miles and thought I had a trophy- well, it wasn’t first place that is for sure.

You might see what @Wranglerfix has to say, and certainly make sure the transmission wiring harness isn’t melted or pinched- had that happen on a truck once- it went crazy.
 
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Good morning gentlemen,

@cvettori55 I do not believe the B0054 and C0057 codes are ECM or tcm related. I will double check when I soeak with my tech. The 1492 code leads back to the battery temp sensor. Have you checked that?

There should be a secondary transmission code to accompany the 0700.

I can test/repair the computers if you would like to send them into me.

Wiring, grounds and voltage should be checked and double checked.
 
Wranglerfix said:
Good morning gentlemen,

@cvettori55 I do not believe the B0054 and C0057 codes are ECM or tcm related. I will double check when I soeak with my tech. The 1492 code leads back to the battery temp sensor. Have you checked that?

There should be a secondary transmission code to accompany the 0700.

I can test/repair the computers if you would like to send them into me.

Wiring, grounds and voltage should be checked and double checked.
Click to expand...
P code = powertrain
B code = body
C code = chassis
 
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Trans module is separate from the PCM on this vehicle. I believe chrysler had an issue with these a while back. When the module fails, the trans is limp moded to 2nd gear.
You really need a DRB II scanner to determine the issue. Once you use the correct scanner and determine that you have "no comm" with the TCM (EATX), check your powers and ground for the module. If all is good, your TCM is more than likely the problem.

P0031 and P0036 are O2 sensor codes
P301 is cylinder 1 misfire. Is it current, engine light flashing?
P0700 is your run of the mill generic trans fault code
C code is chassis related
B code is body related

Also you stated that you finished putting it back together for him. What was taken apart?
 
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Wranglerfix said:
Good morning gentlemen,

@cvettori55 I do not believe the B0054 and C0057 codes are ECM or tcm related. I will double check when I soeak with my tech. The 1492 code leads back to the battery temp sensor. Have you checked that?

There should be a secondary transmission code to accompany the 0700.

I can test/repair the computers if you would like to send them into me.

Wiring, grounds and voltage should be checked and double checked.
Click to expand...
I did replace it with the one in my current jeep. same year just m/t. My jeep wasn't throwing a code for it so I did swap it out yet the code still remains

Also ill do a little more testing I did find the OEM testing procedures through prodemand that I will go through & if those tests are inconclusive i'll defiantly let you know about those computers!
 
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williambmac said:
Trans module is separate from the PCM on this vehicle. I believe chrysler had an issue with these a while back. When the module fails, the trans is limp moded to 2nd gear.
You really need a DRB II scanner to determine the issue. Once you use the correct scanner and determine that you have "no comm" with the TCM (EATX), check your powers and ground for the module. If all is good, your TCM is more than likely the problem.

P0031 and P0036 are O2 sensor codes
P301 is cylinder 1 misfire. Is it current, engine light flashing?
P0700 is your run of the mill generic trans fault code
C code is chassis related
B code is body related

Also you stated that you finished putting it back together for him. What was taken apart?
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What was taken apart: Engine was taken out along with transmission & T-Case. Engine was out for what i believe were gaskets & he had the head resurfaced (my old head). Transmission & T-Case just sat out while the process was being done. The point I got it back was the engine sitting in and mostly everything connected electrically engine wise.
 
Finally got my hands on a scanner not a Chrysler specific one but one that did allow me to access the tcm P0720 - Output speed sensor. Once I cleared the codes i was able to access 1st gear for a second but same code appeared didn't want to test my luck so I parked her for the night.
 
cvettori55 said:
Finally got my hands on a scanner not a Chrysler specific one but one that did allow me to access the tcm P0720 - Output speed sensor. Once I cleared the codes i was able to access 1st gear for a second but same code appeared didn't want to test my luck so I parked her for the night.
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Check and verify the output speed sensor is plugged in. if it is, verify that the harness isn't broken, pinched. Inspect the connector and make sure the terminals aren't corroded or damaged.
If you have access to a scan tool that allows you to read trans info, see what your input/out speed sensor parameters read while driving.
 
williambmac said:
Check and verify the output speed sensor is plugged in. if it is, verify that the harness isn't broken, pinched. Inspect the connector and make sure the terminals aren't corroded or damaged.
If you have access to a scan tool that allows you to read trans info, see what your input/out speed sensor parameters read while driving.
Click to expand...
Just check a moment ago in neutral the output is almost double the rpm. When in reverse or drive its 0
 
The output shaft is spinning in neutral, are the wheels moving? That normally only happens when the transfer case is is neutral. To me it sounds like wiring or the output sensor is fried.
 
Welp blew up a transmission line so I'm at a stop for right now until I can find the line that exploded
 
Idle in park
Engine speed: 670
Output: 1600

Reverse No gas
Engine speed: 660
Output: 350

Drive lil gas
Engine Speed: 800
Output: 1100


New code while messing with it

P0731 - Gear Ratio error in 1st
 
Find the input and output senor on the transmission and trace their wires all the way back to the engine compartment, that's a good start.
 
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