Speedometer problems
Thread Starter
Burning Brakes
Joined: Apr 2006
Posts: 1,043
Likes: 3
From: Toledo Ohio
Speedometer problems
I've got a 92 auto and the speedometer jumps all over the place. Doesn't matter if i'm stopped or moving it goes from 5 mph to 186,45,7,142......you get the idea. The odometer works fine.
I looked for codes and really expected to get a code 24 for the speed sensor, but nothing, no codes.
Any ideas?
I looked for codes and really expected to get a code 24 for the speed sensor, but nothing, no codes.
Any ideas?
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
The diagnostic chart in my 93 factory service manual only mentions "speedometer inoperative" there is no chart for your exact symptoms. The "inoperative" chart suggests checking for speed sensor codes which you have done, also asks to verify that the cruise control works? If you have no codes and the cruise works the next step is to check the S224 splice in the speed sensor wire (green with white tracer). Verify continuity from the splice to terminal E2 in the CCM green connector. If it checks good the final step would be to replace the CCM
Unfortunately it looks like S224 is buried behind the CCM so diagnosis is not going to be easy. Good luck.
Unfortunately it looks like S224 is buried behind the CCM so diagnosis is not going to be easy. Good luck.
Team Owner
Joined: Sep 2003
Posts: 25,364
Likes: 2,730
I believe I'd start with a scanning device that will display MPH/VSS. A Tech1 or similar.
Looking at your profile you mention a 3.54 gear so you've been into something. There's a 2 pulse and a 4 pulse VSS that is used for various years. Maybe - WAG when you changed the speedo-gears to attempt to correct the speedometer you used an incorrect VSS.
I don't know what error will happen when they're mixed but it might be worth an attempt to use a known correct VSS along with the correct count speedo gears and see what happens.
All speculation and just a WAG!!
Good luck!!
Looking at your profile you mention a 3.54 gear so you've been into something. There's a 2 pulse and a 4 pulse VSS that is used for various years. Maybe - WAG when you changed the speedo-gears to attempt to correct the speedometer you used an incorrect VSS.
I don't know what error will happen when they're mixed but it might be worth an attempt to use a known correct VSS along with the correct count speedo gears and see what happens.
All speculation and just a WAG!!
Good luck!!
Thread Starter
Burning Brakes
Joined: Apr 2006
Posts: 1,043
Likes: 3
From: Toledo Ohio
Thanks for the replies. 
I changed the gears about 5 years ago. The speedometer gear was never changed so its always been a couple miles off reading slightly higher. About 2 years ago my speedometer and odometer both quit working. I got a code 24 for the speed sensor, so I installed a new one and everything was good. Until now
I guess it's time to start investigating.
I changed the gears about 5 years ago. The speedometer gear was never changed so its always been a couple miles off reading slightly higher. About 2 years ago my speedometer and odometer both quit working. I got a code 24 for the speed sensor, so I installed a new one and everything was good. Until now
I guess it's time to start investigating.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,008
From: Texas
Replace the VSS. Be sure to use an AC Delco sensor, not one of the other cheaper sensors. I had this same issue, went the cheaper route and still had the problem. Put in a new AC Delco sensor and it's been fine ever since.
