I'll just get right to it... My Speedo reads about 5mph fast.

1) My Wheels and tires are the stock size and diameter.

2) I have a Cobb OTS Stg 2 flash

3) My wifes jeep says that while going the same speed, my speedo reads faster.

4) MY GPS confirms that my speedo is fast and my wife's is correct.

5) (The weirdest thing) If I look at the vehicle speed on the APv2, it reads correct. This tells me that the signal from the ECU is correct and something after the ECU is wrong.

I'm going to get out the DVOM and ohm out the wires and clean the connections. I'm just looking to see if anyone has had the same problem to help cut down on my troubleshooting time.

Thanks,
Rob

Yes this is not unusual, and it's true for many vehicles. The speedo will typically read a few mph on the high side.
You can't fix it by cleaning contacts, it's controlled by pulses from the speed sensor in the transmission.

Yes this is not unusual, and it's true for many vehicles. The speedo will typically read a few mph on the high side.
You can't fix it by cleaning contacts, it's controlled by pulses from the speed sensor in the transmission.

I know and that's what gets me. My APv2 reads the correct speed and it's getting the same signal that the Speedo should be getting. I'm wondering if I might have screwed up when I connected the speed sensor wire to my Pioneer Navigation.

I have the factory manual. I'll see what the signal flow is supposed to be from component to component.

I'll post the answer "if" I find it.

When I worked for SAAB I had a breakout box for the ECU harness on all the vehicals that used bosch engine managment. I wish I had one for Subaru.

All your nav unit does is read the speed pulses from the wire, it shouldn't be able to affect the readings. If it did you'd probably have the speedo cutting out or not working. It's easy enough to check, just disconnect it and see if there is any difference, I doubt there will be.
The only way to "fix" this is to have it electronically recalibrated.

My completely-stock WRX speedometer reads about 4 mph slow.

This isn't too unusual, I've seen it in several cars.

It just bugs thats all. Kind of like that creaking you might hear in your car and you just have to figure out where it is coming from.

whoa.. where have i been.. i've had my car for 7yrs and haven't heard of the cluster speed reading inaccurately.. in any case, i've swapped for an 04wrx cluster.. is that reading off too??

My car reads about 3mph too fast at ~60mph. The speedo being off doesn't bother me, but the fact that the ODO takes the same signal does bother me. 3/60 = 5%, and by the same math, 5% of 60K is 3K. That means my warranty ran out 3K early. Fortunately I didn't need any warranty work in that 3K window, but if I did, I would have been very upset.

I wonder if proving the cluster calibration being off would be grounds for warranty work having to be covered just after the warranty ran out?