Wow here's an odd one...code 24

[d0n_3d]

Out of the blue I noticed the engine light came on as I was driving and the scanmaster shows code 24 which is VSS sensor faulty. Granted I have a GNX dash now and everything was working flawlessly for about a year until now...what in the world do I need to look at for this code? Where is the VSS sensor located? Does this code cause drivability problems or fueling changes? I noticed the car ran a little different...

 

[ChrisCairns]

Out of the blue I noticed the engine light came on as I was driving and the scanmaster shows code 24 which is VSS sensor faulty. Granted I have a GNX dash now and everything was working flawlessly for about a year until now...what in the world do I need to look at for this code? Where is the VSS sensor located? Does this code cause drivability problems or fueling changes? I noticed the car ran a little different...

Look at your speedo cable under the hood. It should poke out of the firewall halfway between where the powermaster goes through the firewall and where the valve cover is. Follow the cable until you get to where the original join is and this is where the VSS should be. In other words the original 2 piece cable is unscrewed and the VSS goes in the middle.

There should be 2 wires from the VSS.

At this point you're on your own as I have no idea where the 2 wires go. I bought my car with the dash installed. But I believe the VSS only controls TCC lockup.

Does your car still lockup as per normal??

 

[TurboJoe3.8]

Don- did you get the engine light after you used the cruise control? The reason I ask is that today I had mine out for some road time and I got the same code as you, but right after I was using my cruise control- I also have a GNX style dash installed too- after I shut it off, the light clearedand I took it out again and used the cruise control and got code 24 again, shut it down and it reset again, took it out again and didn't use the CC and drove it over 2 hours on the highway and no code! Maybe somebody here has the answer for us- thanks, Joe

 

[JDSfastGN]

code 24 changes something, i can't remember exactly but when ever my dads car would get that code it would run rough. And if the VSS isn't working then the TCC is not locking and the tranny is going to get a lot hotter as the fluid path to the cooler is only partially open before lockup.

 

[Black Car]

The VSS sensor send its' signal to the VSS buffer. It is a light green rectangle box with the letters AC on it. It is located behind and slightly above the radio. Pain in the A** to get to. Mine was taped securely to the harness.
When my buffer got warmed up it would send wild speed siganls to the computer. Anywhere from zero to 220 MPH and would change every 1/100 to 3/10 of a second. DS showed these changes but the SM didn't.
When I activated my cruise, it might lock in on say 50 MPH but then in 1/10 of a second the computer would say the speed was 25 mph, so it would floor the gas. Then in the next 1/10 of a second it would say 200 mph and would shut off the fuel because the speed exceed the MPH limit in the chip.
When just driving and the 200+ mph occured, it would feel like a slight miss.
The longer the buffer reported the greater the miss. Spent six months trying to find this miss. Drove my batty.

Never got an error code so I don't have a answer for your problem.

Gary

 

[SloGN]

the speed sensor play a bigger factor than just controling the TCC lock-up. The stock ecm uses the VSS signal and other data to determine the LV8 (engine load)

i think in a break down in the chip it's LV8 = rpm X mph X tps. so using that the speed sensor also plays a part int he fueling and timing tables also.


ever wonder whats causes freaky knock when the wheels spin?

when the wheels spin it whiplashes the VSS/speedo and when it does this it changes the timing/fueling tables in the ecm. i have some direct scan files to prove it.

 

[ChrisCairns]

the speed sensor play a bigger factor than just controling the TCC lock-up. The stock ecm uses the VSS signal and other data to determine the LV8 (engine load)

i think in a break down in the chip it's LV8 = rpm X mph X tps. so using that the speed sensor also plays a part int he fueling and timing tables also.

Nope. Check out what the big brain geeks ( ) have to say.

http://www.turbobuick.com/forums/showthread.php?t=52885&page=1&pp=20&highlight=lv8

 

[d0n_3d]

The VSS sensor send its' signal to the VSS buffer. It is a light green rectangle box with the letters AC on it. It is located behind and slightly above the radio. Pain in the A** to get to. Mine was taped securely to the harness.
When my buffer got warmed up it would send wild speed siganls to the computer. Anywhere from zero to 220 MPH and would change every 1/100 to 3/10 of a second. DS showed these changes but the SM didn't.
When I activated my cruise, it might lock in on say 50 MPH but then in 1/10 of a second the computer would say the speed was 25 mph, so it would floor the gas. Then in the next 1/10 of a second it would say 200 mph and would shut off the fuel because the speed exceed the MPH limit in the chip.
When just driving and the 200+ mph occured, it would feel like a slight miss.
The longer the buffer reported the greater the miss. Spent six months trying to find this miss. Drove my batty.

Never got an error code so I don't have a answer for your problem.

Gary

this is EXACTLY what is happening to me other than I no longer have cruise control on the car AND I have a non-lockup converter now...my car was "missing" under normal cruise almost like a bad MAF sensor............I was even at a local cruise here 3 weeks ago and the car died on me 3 times coming out of parking lots...i checked all over for what was causing this but no codes came up...finally the code 24 came and now this makes sense...so I guess I have to check the green buffer box by the radio which I know for a fact should be OEM...the VSS sensor in the engine compartment is brand new since it came with the new cable and GNX dash a year ago......but I'll check it out...hmmmmmm interesting thanks guys

 

[bishir]

I'm having a code 24 issue right now and it seems like the car wants to buck and surge around 8-10lbs of boost. I went ahead and bought a new sensor, but haven't replaced it yet. Any other tips on replacing it?

 

[DavzGN]

First thing I would check is the wire connections to the new VSS sensor. I know I have get a 24 code every few months on my GN with a Kenne-Bell GNX dash, but I haven't had the opportunity to check the connections on mine yet.

David
87GN

 

[57loboy]

Does anyone have a pic of what should be in place where the 2 cable join together under the hood? I have a non-lockup trans in my car now that will be swapped out as I want a lock-up one and want to be sure I get everything connected appropriately...

Right now I have just the speedo cables that join together with nothing in between them. I am not sure if the buffer is still in place under the dash. I've not noticed any unconnected wires in the area of the cables under the hood...

Thanks!

 

[DavzGN]

If you have the stock dash the VSS sensor is under dash on the back of the Speedometer assembly. It's only moved under the hood for some of the GNX style dashes.

David
87GN

 

[VadersV6]

If you have the stock dash the VSS sensor is under dash on the back of the Speedometer assembly. It's only moved under the hood for some of the GNX style dashes.

David
87GN

Thanks for clearing that up. Thought I was missing the VSS sensor. I also have nothing where the 2 halves join. If the VSS sensor wasnt there, and/pr the buffer werent working, would you get any MPH reading on the scanmaster? My scanmaster MPH readings are fine.