Disturbedtransam

I just replaced my vehicle speed sensor. The car was throwing a code for it. I am still having the same issues as before I switched the sensor. Except I am not throwing a code now. The issues I am having is no shifting and my speedo is not working at all. Any help would be greatly appreciated.

performabuilt

iTrader: (25)

I can tell you that its not a trans issue. The PCM will not comand shifts without the VSS I would check wires and harness along with fuses somethings wrong in one of those areas

MUSTANGBRKR02

iTrader: (91)

I believe the VSS sensor is pin number 20 and 21 on the red pcm connector should be a green and purple color both with black stripes if i remember correctly. Might have a pinched wire if you disconnected and connected it a few times. If this is it try this site for a pigtail.

http://www.repairconnector.com/

Disturbedtransam

I was told my tranny was in limp mode when the old sensor was in is their anything to reset this when the new sensor is installed?

Disturbedtransam

I read through the schematics last night and everything looks like it leads back to the PCM that or the trans.I just had this car done little over a year ago and I dont even think I have 1k on it. I scanned the car I am not throwing any codes at all.

Disturbedtransam

There is two connectors to the PCM what one am I looking at? I just put the old sensor in and now I am not throwing a code. But still no speedo and shifting.

remauto1187

iTrader: (1)

Pull the ecm fuse for a couple mintues then reinstall OR pull the negative battery lead for a couple minutes. Clears everything. Then see where you are at...with the new vss installed.

Disturbedtransam

Not sure where the ECM fuse is but I did pull the battery terminals for about 20 mins. Still having the same issues

RevGTO

iTrader: (12)

Are you running a stock or hi-stall converter? I ask because when I went from a 3000 to a 3600 converter, I threw the same code launching at the track. Replacing the Vss didn't help. Tuning out DTC's (PO751 ?? IIRC) cured it.

14k

I hate to be this guy but I'm grave digging to help solve my problem.

I'm having the EXACT issue with my z28. What's the easiest way to check the wires from the vss to the pcm without pulling the complete harness? Is it safe to drive my car about 2 miles in limp mode to mg job so I can work on it?(i don't plan on driving it until I find the vss problem other than pulling it in and out of the shop during work hours) I have 1st and 2nd gear if shifted manually but trying to manually go into 3rd it acts like another neutral. Pcm reads 0mph so I know it's a vss problem. I changed the sensor that now points towards wiring. If all else fails can I find the wires at the pcm and run my own vss wires to the plug?

Exeodus

iTrader: (1)

I wouldn't drive it in limp mode due to the excessive heat that will occur by not shifting out of first. Heat is the main killer of the 4L60E.

mrvedit

As mentioned I would be cautious about driving it very far, but 2 miles should be fine. If you have a scanner, keep an eye one trans temp.

I suspect the most common VSS wiring break is between the main trans connector and the back of the trans. First look for damage due exhaust heat or road debris.

14k

I can manually shift to 2nd. I have to drive it to my job its kinda hard to find the problem in an apartment parking lot.

mrvedit

If you don't have a hoist at work, I suggest taking it to a trans shop. If it isn't a corroded connector or obvious break, it may be necessary to remove the driveshaft and the rear trans mount (while supporting it with a tall trans jack) to lower the trans enough to reach and repair the main trans harness.

14k

I did the whole swap on a lift. But at work I don't have one. I do have tall jack stands and the tools to pull the driveshaft to lower the trans.

mrvedit

Sounds like you have the experience and tools to do it. I didn't know how dirty you wanted to get.

Have you replaced your VSS?
Have you checked for corrosion on the VSS connector?
I regularly read here that someones VSS went bad; they are relatively inexpensive - ACDelco is $22 on Amazon and generic ones are cheaper yet.

If that doesn't fix it for you...
With the Battery + disconnected, I just checked my VSS connector with an Ohm meter to Ground. My purple wire was just 1.5 ohms to Ground (probably Ground within the PCM), the other was infinite. That might help you figure out which wire is bad.
Sure, you can run a small gauge wire(s) from the PCM to the VSS. Just keep them away from the exhaust and note that automotive wire is more heat resistant than e.g. speaker wire.

14k

Ill do whatever to get my car running. Lol.

If replaced the sensor. I haven't had time to mess with it to check the wires etc. But I might just run my own wires to avoid the hassle of searching for broke wires. I tried for alittle to find the wires at the pcm with no luck. Do you have a pic of them by chance? Do I just need to run 2 wires?

mrvedit

On a '99 to '02 PCM the VSS goes to pins 20 (Lt Gnd/Blk) and 21 (PPL/Wht) of the RED connector.
I won't show a picture because my harness is custom made and would confuse you.
You only need to run two wires. Unless you have the special PCM pins, you will have to splice them into the harness near the PCM. Use auto wire to handle the heat. Here is a trick for twisting two or more long wires together into a "bundle". Hold one end of the wires together in a vice. Tighten the other ends into the chuck of a drill. Turn on the drill and twist them as tight as you like; note that as they get shorter this way, you need to start with extra length.

14k

I read gère on ls1tech everything could be fine wire wise but with the ss3600 or causes a false vss low voltage?


"had limp mode issues after going up to a Yank SS3600 from a TCI SF3000. In my case, I had to tune out P0757 as above, also P0502 -VSS circuit low voltage (which had nothing to do with voltage, the VSS was confused by my stall and tires) and one or two others that I don't remember offhand."


Im going to check the wires for continueity layer today im hoping that the wires broke cuz if not Idk what else to check for.

14k

Everything iv done so far


New vss sensor
New vss pigtail
No break in wires verified with multimeter
Vss sensor works when drivershaft turns verfied with multimeter
Checked all fuses
All other guages work in the car.

I'm lost Idk what else to do.