Code 15 speed sensor

[jeff1234]

I have looked this problem up and haven't seen anything more than discussions about bad sensors or damaged wires. I have a new speed sensor and an old one both give the same results so I dont believe that the sensor is the problem. I have examined my wiring and can find no abrasions or breaks etc. I am wondering if a jerky speedo cable might not have something to do with it. I have noticed that my needle is making a very small jump going down the road. If the cable was resisting being driven perhaps it pops by the next contact to fast to register a signal. What do you all think?

[RoadWarrior222]

I'd think that the snags in the cable would be taken up by lash in the cable, not a lot of opportunity for the bottom end to skip unless the gear is carved up.

In my Voyager, where the harnes goes by the back of the battery, the corner of the battery had chafed through insulation, just enough to make a small hole through, moisture did the rest, there was an inch of green oxide each side, which strangely wasn't as conductive at copper. What I'm saying with that is, any small nick or crack could have caused a similar failure, so you may need a finer fine toothed comb to go through the wiring with, so to speak.

[cordes]

The speedometer cable is not related to the code 15. The electronic portion does not go to the speedometer at all.

[jeff1234]

RW222, The more I thought about it, I realized you were correct. The speed sensor isn't driven by the cable, it is driven by the gear on the right side trans output. My best recollection is that my gear was in good condition. My particular speed sensor has the speedometer cable and signal cable attached to it, so I am not sure what Cordes meant by his statement. I went to the Mini-Mopar site and read up. One thing caught my eye which was that Russ says it helps diagnose other components. The only other thing that is going on all of the time is that I get a detonation indicator light (shelgame cal/green triangle on rally pack gauge). I have come to believe that this may be a false signal although I need to prove it yet. I have a stethascope that I am going to rig up to listen to the engine noise when the days warm up a bit. I have heard knock before but I really don't hear it now in spite of the indicator light. I do wonder if the two have anything to do with each other. I have a 523 trans that I installed instead of the 525. I am using the speedo drive gear from the 525, could a mismatched tooth count cause the problem? I have checked my speed with my GPS and it is off by about 3 MPH.

[RoadWarrior222]

I think it would have to be a good 20% off before the sensor would get faulted for the wrong gear.

[supercrackerbox]

As far as I know, the gears are interchangeable, and the computer doesn't know any better regardless of which gear you run.

The last sensor I changed out was in my Daytona (no cable). The sensor itself was starting to bind and stick, causing the speedometer to jump all over and trip a Code 15. Does your sensor spin freely with no resistance?

[jeff1234]

Because it was new in the summer of 2012 and because I don't want to lie on a cold garage floor in Wisconsin right now(LOL) I am going to assume that its is OK. The old one spun free as well. I was just through Lincoln a week or so ago on my way to an equipment service in Hardy, Ne. Not to bad down your way.

---------- Post added at 03:23 PM ---------- Previous post was at 03:14 PM ----------

According to the Mini-Mopar site it only diagnoses on decel only after 7 or more seconds of closed throttle if engine RPM is 768 RPM higher than where it should be and there is no signal. I did notice that there is alot of end play up and down with the gear. If the shaft is going up and down and moving the magnet up and away from the reed switch, that would possibly constitute a no signal.