2005 Jeep

Shane Technician Summerville, South Carolina Posted   Latest  
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Electrical
2005 Jeep Wrangler Unlimited 4.0L (S) 4-spd (42RLE) — 1J4FA44S95P303345

Hey guys I just wanted to pick your brains about a vehicle I have. Its an 05 Jeep Wrangler 4.0L. The customers original complaint was that the speedometer would not read. So I went to the VSS that sits in the transfer case and disconnected the connector. I checked for my 5V reference, my sensor ground, and my PCM signal. I had a good 5V and ground. The signal wire also read 5V when disconnected. I then reinstalled the sensor and back probed the reference voltage and it dropped to zero. Then I hooked up my scope to the senor signal and sensor ground to check for an output and none was present. I determined the vehicle would need a sensor. I installed the new sensor and the speedometer worked. Roughly 300 miles later the customer returned with the same issue. I ran through the same diagnostic steps and it pointed at a failed sensor. I installed the sensor and did my own 50 mile test drive and found no issue with the speedometer. 2 days later the customer returned with no speedometer operation. I decided to test a bit differently now by building my own stand alone wiring. I created my own ground, 5v reference and output. I removed the old sensor and plugged it into my wiring and found no sensor output. I then picked up another new sensor and connected to my wiring and received a sensor output on the scope. What I am trying to figure out is what would cause these sensor failures repeatedly. If anyone has an idea or a tip I would greatly appreciate it and if you need me to upload any data just ask. Thank you.

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Interesting
Mike Owner
Cromwell, Kentucky
Mike Default
 

what brand sensor are you using if you don't mind me asking? I have issues almost weekly with cheap electronics anymore. anytime I see dorman on a box we take bets on if it will work or not :(

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Shane Technician
Summerville, South Carolina
Shane Default
 

Mike the first two were both from O‘Reilly’s and this new one is from duralast

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Gary Owner/Technician
Buena Vista, Colorado
Gary Default
 

Right on, Mike I've been having problems for years using aftermarket sensors on Chrysler products. Period...

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Ricardo Diagnostician
Plymouth, Michigan
Ricardo Default
 

Had a similar issue NOT on a jeep but on a ford excursion the sensor would go bad after 10-15 miles and it ended up being the missing main ground between engine block and frame. The terminal was broken so a new terminal and a clean ground spot on the frame fixed the issue

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Shane Technician
Summerville, South Carolina
Shane Default
 

This ground is actually a sensor ground internal to the PCM. I will double check the PCM ground.

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Gary Owner/Technician
Buena Vista, Colorado
Gary Default
 

Shane, Is the VSS ground spliced with another ground inside the wiring harness? I had one on a Ford Tempo a number of years ago and found it by watching its voltage graph on a scan tool. A wiggle test finally located the splice on top of the cam cover. It was very sensitive to heat and vibration.

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Brian Diagnostician
Goshen, Indiana
Brian Default
 

I would try an OEM sensor and see if that lasts longer.

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Shane Technician
Summerville, South Carolina
Shane Default
 

Unfortunately mopar no longer makes this sensor.

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Geoff Diagnostician
Lahaina, Hawaii
Geoff Default
 

I'm surprised you say that when Repairlink shows it available. This is part # … right? Similar to what Keith said, and presuming I got the look-up correct, I would be curious about any other mechanical defect, like a shaft wobble adversely affecting the mechanical component of … That's a weird looking one for sure.

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Shane Technician
Summerville, South Carolina
Shane Default
 

That is the correct part number, but when I went to my parts department they advised me that it was not made anymore. I will double check with them though

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Geoff Diagnostician
Lahaina, Hawaii
Geoff Default
 

Have him run a locator. My Repairlink account goes to various dealers in Cali.. In any event that is an odd configuration for a speed sensor for sure! :-)

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Dwight Owner/Technician
Oceanside, California
Dwight Default
 

A new OEM on ebay. ebay​.​com/itm/Jeep-CHRYS…

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Olle Instructor
Albert Lea, Minnesota
Olle Default
 

Could you use a DMM on the mA scale, connect between ground and the signal wire? How many mA does the circuit draw? Should be a fairly low current. If too high, the sensors will fail.

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Shane Technician
Summerville, South Carolina
Shane Default
 

I will check that when I get in tommorow

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Keith Instructor
Commack, New York
Keith Default
 

I think it would be very important to remember the conditions of where the sensor is located as well. What would happen if we had an excess hear buildup starting in the transfer case ? Improper fluid , poor rebuild etc ... Could this be the reason for multiple failures ? Would it be worthwhile to try and drive this vehicle hard and long and then right onto a rack to see some case temperature…

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Geoff Diagnostician
Lahaina, Hawaii
Geoff Default
 

KDF- "Opus IVS Instructor" ? Is this why there's no new videos?

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Shane Technician
Summerville, South Carolina
Shane Default
 

Keith I didn’t think about that situation, I will definitely try this tomorrow and let you know the result.

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Stephen Technician
Gallatin, Tennessee
Stephen Default
 

Since the new sensors all worked for a period of time; I doubt that the sensor is failing on it’s own. I think putting in a OE sensor will prove that when it quits too. The original failed in a shorted mode, the Ref 5v was shorted to ground. It would be worth knowing if the others did too. The mode of failure indicates that it is being overcurrented or over or reverse voltaged. It can hardly do…

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Shane Technician
Summerville, South Carolina
Shane Default
 

If the sensor ground was shorting then shouldn’t it have a negative effect on the PCM also?

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Stephen Technician
Gallatin, Tennessee
Stephen Default
 

The PCM grounds can handle higher current than the sensor. When a main ground is unable to carry all of it’s normal current, the current will move onto other grounds. How much current depends on what the demand is vs the path(s) to carry it. The circumstances of the repeat failures indicate that the cause is on the truck. The mode of failure of the sensors indicate that it is electrical. Is the…

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Shane Technician
Summerville, South Carolina
Shane Default
 

I know the first sensor failed after 300 miles and the second sensor failed after 150 miles. I have installed the new one yet because I was trying the determine what would cause the sensor to stop operating. The only code I get is a VSS Rationality code.

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Gary Owner/Technician
Buena Vista, Colorado
Gary Default
 

Shane, The only code I get is a VSS Rationality code. By "rationality code" we're saying what?

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Shane Technician
Summerville, South Carolina
Shane Default
 

It is a VSS Rationality/Performance Code. Rationality should mean the PCM cannot decipher the signal correctly, but I know the sensor is putting out no signal in the first place so I’m assuming it is referring more too the performance side of the sensor

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Gary Owner/Technician
Buena Vista, Colorado
Gary Default
   

I'm curious as well, Shane I had a long-time customer with a 2001 Dakota 4.7 that ate two aftermarket cam sensors, one each year. Each set a P0340 code, I tested the connector, all was good as far as reference and ground were concerned. At that point, I changed both the cam and crank sensors with no result. The 3rd AM sensor lasted only 6 months, so I went to OE, with one lasting only one…

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Shane Technician
Summerville, South Carolina
Shane Default
 

The code is actually a P0501 (Vehicle Speed Signal Performance). I'm going to drive it this morning and scope the back of the sensor while driving to see if I am getting a voltage spike that will kill the sensor.

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Eric Owner/Technician
Edgerton, Wisconsin
Eric Default
 

Scope the sensor signal and ground circuits while cranking too. Just to make sure you don't have an issue with the high current starting circuits. I've seen that problem cause repeated sensor failures along with modules.

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Gary Owner/Technician
Buena Vista, Colorado
Gary Default
 

Good idea, Eric...

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Mike Mobile Technician
Charleston, South Carolina
Mike Default
 

A few things come to mind on this that haven't already been mentioned. First, I honestly would bank on junk sensors. I wouldn't be surprised if the O'Reillys and Duralast sensors didn't come off the same manufacturing line. Probably not good news if the part is obsolete. Order one off Amazon from china and watch it work for 100k miles! I would definitely be looking for any mechanical issues…

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Gary Owner/Technician
Buena Vista, Colorado
Gary Default
   

So are there any other codes or symptoms you could chase? If not and you still think the issue is electrical I might try and take resistance measurements on a new sensor versus a failing sensor or better yet the same sensor before installed and then after it fails and see if you can spot a change. Not really sure if you would be able to determine a faulty sensor vs. something causing the sensor…

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Geoff Diagnostician
Lahaina, Hawaii
Geoff Default
 

Gary, Did you see what this VSS looks like? i​.​ebayimg​.​com/images/g/PtUAA…​.​jpg

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Shane Technician
Summerville, South Carolina
Shane Default
 

Well I put a new sensor in and then drove it 108 miles. I had no error occur and asked the customer to come pick it up. After he drove 2 miles the sensor failed. The dealership decided not to spend anymore time on it and shipped the car out, so I will never know fully what was happening.

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Gary Owner/Technician
Buena Vista, Colorado
Gary Default
 

We all have our baffling cases, Shane, it's just part of the business. I have one on a Toyota Tundra that I'll post when I get time. Unlike yours, the vehicle is evidently fixed, but I don't know why {:0(

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Geoff Diagnostician
Lahaina, Hawaii
Geoff Default
 

So much for the dealers never giving up! Sheesh. That's sad to hear bro. Not YOUR fault, I understand, I mean the idea of a dealership saying "we don't know, go away!" I talk with plenty of other dealer techs that sometimes WISH they could do that. ;-)

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