Hello. I know I need to replace the VSS, because my speedometer doesn't work half the time, sometimes it shoots up to 100 MPH while in park (idling) and the D4 light will start blinking. The check engine light also comes on, but ONLY when the D4 light is blinking. This is an off and on problem, but when the speedometer starts acting up and the D4 light starts blinking, the transmission shifts weird. It will down shift and slip and do all kinds of weird things. The car acts like it is running out of gas. It has loss of power and everything. Only while the speedometer stops working, and the D4 light starts blinking. Is it possible that the VSS failure can cause these other symptoms too? What do you guys think? Thanks!

 

It's very possible, the auto trans changes gears based on rpm and vehicle speed, and it's a relatively common issue. The problem being intermittent is a sign that is an electrical problem, in this case the speed sensor...which luckily only goes for $15-$30 depending on brand and store

 

But would it also make it have loss of power, like a slight shudder while accelerating? It seems to bog too. And when the problem is happening, I also notice it seems like it is harder on gas, and I can kinda smell that it is running rich.

 

Loss of power and rich condition could be a result of limp mode when the mil comes on when the problem occurs, although I could be wrong but I found this that may help you
http://techauto.awardspace.com/vss.html

 

I had this issue on my 96 accord. It was the speedo cluster. Replaced it and never had an issue. I think the motor was shorting out on the speedo but it could be the vss as previously stated. Without vehicle speed the ecu may not know what to do with the tranny.

 

Both issues are very common, but the d4 light flashing is a fault sign for the vss. I think what may have happened on yours is the circuit board commonly comes loose and requires resoldering

 

VSS is what the TCU uses to determine a down shift. If the VSS is faulty or gives off an incorrect signal the transmission may down shift undesirably/dangerously at highway speeds. If the down shifting is erratic enough to make the care undriveable, but you still need to use the car to put put around, disconnected the VSS sensor. This may cause the transmission to go into a limp mode but it will not be dangerous to drive, just slow.
VSS is also what the ECU uses to initiate fuel cut off for the speed limiter. If the VSS is causing a false reading and the speedo is hopping up beyond 120MPH the ECU will pull/cut fuel and the engine may very well sputter/die at a lower speed. ECU *thinks* you are speeding and pulls the fuel, even if you are only going 30MPH actual.

http://techauto.awardspace.com/vss.html#Solutions

Personally, I would pull the codes first. Most likely the codes you will retrieve will be CEL #17, and/or D4 #4. If only these two codes show up forego the diagnostics at the moment and pull the VSS sensor, scroll down the above link and read up on how to clean the VSS. If the sensor was dirty then it was most likely the cause of your erratic shift issues. Clean it, reinstall and see if the speedo stops hopping around and the car shifts correctly.

If the cluster was the only faulty part the drivetrain would not be affected.

 

Great info Mad Mike, you hit the nail on the head. I replaced a bad board on my instument cluster and fixed my speedo issue. Just recently my 94 ex started losing power...idle was erratic and speedo started jumping again...the CEL came on for the first time since I owned this vehicle..#17...VSS. The problem is intermittent ..when the speedometer is working the car runs well...when the VSS starts failing I get all sorts of performance problems. Thanks for the info, much appreciated.

 

Update...I went to the salvage yard and got a VSS for eight dollars, installed it and my 94 EX is running excellent.

 

My speedometer is erratic too. Sometimes its all over the place from 0-140, other times it works okay. When it works, I can get the cruise control set for only a few seconds. When the speedometer is not working, the cruise won't work at all.

Here's the kicker... NO CEL and NO codes. Ever. And the D4 light doesn't come on AT ALL. It is constantly off, but the others work fine.

So is this a bad speedometer circuit board, or a bad speed sensor?

1997 Honda Accord LX Automatic 4-door

 

if its linked to the cruise control then its prolly the vss ... they got em on ebay and amazon for $15 .. i got mine off amazon

 

That is the only real way to diagnose any automatic transmission codes/issues.
Although your car is OBDII and you can get the power train codes from the 16pin port, the problem is that the OBDII trans codes are not well documented. While the OBD I ones are. Steal a light from one of the other indicators and place it in the D4 slot. Then you will be able to read the codes for the TCU.

 

same **** is happening to me, have u fixed it and was it the speed sensor?

 

Yeah, I don't think he's coming back.

Pull the VSS, clean the internals, verify the main connection at the VSS is clean and tight, if the pins are loose, corroded or busted your ECU will not get the correct readings and may cause erratic shifting and other performance issues. Use the 'tech auto' link provided above to diagnose.