jbtvt

There are quite a few threads on here about the VSS vehicle speed sensor causing major issues with the auto trans, but I haven't seen any on the 5 speed. My issue is different than the autos, which is good because it will at least drive, but I've been chasing an intermittent mild shudder for months now. No codes, and every other mix part has tested out good.

Sb5walker got me thinking about it, in a post where he says that a noisy sine waveform from the sensor can make the ECU think you're at governor speed and it will cut the fuel, which would seem to affect the 5 speed drivers as well as automatics.

Is there a resistance test for the VSS to confirm the problem, given how pricey these things are? I don't see it covered in the FSM, but there are about 200 different pages it could be covered under, so maybe I'm looking in the wrong spot.

MudHippy

It's funny you mention that, I was just talking about the code 11 issue. I can tell you for certain it's been an issue with the driveability of my 88 3VZ-E w/manual transmission for many years. And I still haven't solved it. Which you've already read I'm sure. I intend on eventually replacing the COR first and seeing if that does it. We'll see...

Check out the article on VSS failure for how to test the VSS.

FYI, replacing it means replacing the entire speedometer assy(speedometer/odometer/VSS). And they aren't cheap...

jbtvt

This stutter is pretty mild, when it happens it's 1-2 vibrations a second, for 5-30 secs at a time, and no codes. I'm hoping that it's just the ECU trimming fuel and not actually losing power.

As it happens, I swapped out my COR today also. It got wet so I wanted to rule it out and had a donor which I found out also had a leaky windshield, but the capacitator was in better shape. Since the contacts are still good on this other COR, I was going to try just swapping out the capacitator and resistor - a 25-30v, 130+/- uF capacitator rated for 125 degrees C, and (I think) a 470 ohm resistor. Way cheaper than a new one, I'll report back after trial...

Anyway, I couldn't get the PDF to load on the motors page, but I found this - http://www.autoshop101.com/forms/h36.pdf
Unfortunately I have no oscilloscope. BUT, I was thinking, maybe throwing a small resistor in line with the reed switch output would filter some of the errant (and hopefully lower) voltage that's tricking the ECU. I do have a donor which is a 94 and an automatic, so I think I'll try to throw that in, or cob it together somehow tomorrow, and deal with it from there if it's not swappable.

GreenJerseydevil

I have the same problem. I get a code 42 runs rough.
I can't find any info what so ever On The vss.
What it looks like, location, or how to test it.
Total loss of pwr on take off. Every thing is new motor ecu sensors ect.
This sob should run like a brand new truck!!!
How commen is it for it to go bad? How do I fix it?
Wtf???!!? Every day I have replaced a part for the last six months.All Toyota parts so you could imagine what I've spent. After the harmonic ballencer mark issue with after market bull. I'll stick with the stealer parts if I can.
I'm not able to post pivots from my phone other wise I would.

GreenJerseydevil

Here I see it must be the last Example reed switch? In the cluster?
http://www.autoshop101.com/forms/h36.pdf

jbtvt

Depending on the year you may have a mechanical (cable) or electronic (two wires) leading to the speedo. The sensor itself is at the rear of the transfer case regardless. I eliminated mine as a source of error by temporarily disconnecting the cable from the rear of the gauge cluster - no change in symptoms for me, but I never had a code 42.

There are thread on here detailing how to replace, convert from one speedo to another, etc. I would play around with a square wave generator, reed switch replacement and resistor in circuit before spending 200 on one, but depending on your skill level the best bet may be to put a new one in.