GPS plus flat straight road. Somewhere that you can maintain a good constant speed. Preferably higher speeds if your area allows it. The higher the speed you can maintain the more accurate your reading will be.
Best Speedometer Calibrator?
- Thread starter BoomerBob
- Start date
HiluxSurf SSR-G
Senior Member
So the 1996-2002 USDM 4Runners do not have the speed sensor that's located near the tip of the transfer case?
Speedometer calibration cannot happen through the ECU/OBD-II port. Not only is the ECU not programmable, the speedometer SENDS the signal to the ECU, not the other way around.
On ABS equipped 3rd gen 4Runners (almost all of them), the system goes like this:
ABS wheel speed sensors -> ABS computer -> Gauge cluster -> ECU (and 4WD computer, diff lock ECU, etc.)
To calibrate the speedo (and the speed the ECU sees and reports via OBD-II), you need to interrupt the signal between the ABS computer and the gauge cluster and use a calibrator there.
I chose the Dakota Digital speedometer calibrator, and installed it in the passenger kick panel next to the ABS computer:
-Charlie
EDIT: Also note that gearing will have no effect on the speedometer, since the speed signal is taken from the wheels, not the transmission/transfer case output. Only tire rolling diameter will change the speedo reading.
phattyduck
Elite Member
For the most part, no. Some of the early base models had no ABS, and they did get the speed sensor.
-Charlie
I haven't been able to find a definitive answer but, after reading as much as I can find on these forums, I'm suspecting that for the 4Runner models that came with both the 15" and 16" rim sizes, the stock speedos are all calibrated for the base 225/75R/15 tire size giving the ones with 16" rims a low speedo reading.
My speedometer sync's up perfectly with the 265/70R17's I have on my 4Runner right now.
Thanks for chiming in! I may save me the same countless hours as I'm kind of a perfectionist with stuff like that. One question though, can you tell me if/why the Dakota Digital device shown earlier in the thread was not a good option for you?
Your speedometer will be off by about 3 percent. In other words, speedometer shows 70 mph you might be doing 72 mph. This is assuming your speedometer shows the correct and accurate speed with 265/70R16 tires.
jross20
New member
Well, it is a bit hard to install in terms of the risk due to how short and fragile some of the wires are. But, beyond that, even after setting everything up the speedo would keep "flickering". So, say I am driving 55 mph, every so often the speedo would jump all over and stuff. This rendered the cruise control useless as the truck would suddenly try to floor it all the time.
I actually called dakota who pretty much offered no advice. Said what I described was "not possible".
I got home, removed it all and did my best to mend the wires (which is thankfully holding to this day). Returned the device and lost a good bit of money selling the larger tires and buying normal size ones again.
I was so freaked out about the speedo never working right again...
Oh wow, that is good to know! Thanks for sharing your experience. I've had a similarly bad experiences messing with the wires on another vehicle so I know what that's like. Glad to hear to hear you at least got it working in it's stock configuration.
phattyduck
Elite Member
Funny you mention 55mph. That is the only speed where my Dakota Digital calibrator has a little glitch. Rock solid otherwise.
I've rewired a few Toyotas over the years, so the wiring side of it didn't seem particularly difficult for me.
-Charlie
