Hey guys. I picked up an 06 S2000 recently that needed some love, but kinda have no idea where to start. When I picked it up, I immediately changed the battery because the old one died. After driving it about an hour, the speedometer and odometer stopped working, check engine and steering wheel light came on, and fuel gauge acting funny. Engine and driving didnt feel different, but I never really pushed the car until 1000 miles later after getting the car home and changing the oil and fluids.

When I went WOT last night and hit about 7k, the car just lost power as if I hit a wall, so apparently vtec doesnt engage. I also finally pulled the codes from that check engine light and got a bunch of codes:

P0720 output speed sensor
Antilock Braking System: 15, 16, 25, 27, 61, 62, 65, 66, 83, 86
supplemental restraint system: 71-10 and 81-64

Anyone have any ideas what is going on with my car? I'm fairly new at diagnosing these types of things. I read something about a yellow box modification that could mess with the odometer, but didnt see anything coming off the transmission. The car is pretty much stock from what I can tell.

 

Could be a lost wire contact. If the speed sensor quits the EPS light will come on and the speedo will not work. Check at the trans and see if wires are connected. l Go on one of the Honda parts sites and pull up speed sensor and it will show you where it is located. Check the wires and follow them up to speedo. Sensor could also have gone bad and is an easy replacement and not costly. Can;t help you with the ABS as I removed it from my 03 totally. Good luck!

 

Was the car fully warmed up when it stopped revving at 7K?

The car has a hard rev limiter at 7K RPM if coolant is not at operating temp.

 

Yellow box? Car heavily modified? Did VTEC ever engage during your ownership or your test drive?

This many issues make me think there's a major grounding issue.

Still got the 2002 in your profile? Maybe someone local in Not Applicable can help -- sounds like California.

-- Chuck

 

Ok I'll try looking to see if I find anything weird. If I replace sensor, do I use Honda OEM or any aftermarket part will work ok for this?

Actually, you are probably right. I only warmed up the car sitting at idle for like 10 minutes before I took it for a spin.

I dont have the 2002 anymore and have disappeared the last couple of years because of that. As for vtec, I never engaged it because I didnt want to push the car during the 1000 mile drive and not really knowing the history (bought from auction). Plus, all the dash lights didnt really help give me peace of mind either. And yes, I'm in Cali. Maybe I'll see which good shops are around socal if I cant get this figured out

 

I would use Honda oem parts for this if needed. Pretty cheap, I replaced mine about 2 yrs ago.

 

So I replaced the speed sensor on the transmission with one from honda. At first, it took awhile for the speedometer to start working... but then sometimes it still doesnt work at all or reads realllly low (incorrectly). I looked underneath and didnt see a yellow box, so I doubt it's related to that.

As far as vtec, it works. I just need to remember to warm up the car quite a bit before trying to stomp the gas.

Any other things I should look for regarding the screwy speedometer?

 

I would check all the main grounds right away. I believe I saw a post on here with all of them pointed out. In the shop manual as well if you have a copy of that or have access to one. Issues like this can defintely be grounding issues.

 

Especially, check ground strap that goes to back of cylinder head.

 

^ #1 cause of erratic speedometer