New owner of 2007 outlander 4wd with the 2.4 and auto. We’ve previously owned a 13 model so when our daughter needed a car we grabbed this.

She noticed the speedometer reading is out. I’m aware and have seen loads of threads about it usually being under actual speed by a small margin for legal reasons. This is the opposite. Speedometer is reading lower than actual speed by about 10% so if she sits on 100 on the dial the car is actually travelling at 110.

Tyre size is correct standard size.

Obviously this is a dangerous situation.

Any thoughts? Is there a sensor or sender that can cause this which can be replaced to solve it? Does it require computer resets etc etc?

Thanks.

 

The next time that tires are needed, you might consider buying lower profile tires on the same rims. Circumference of the running tires will be smaller than that of the present tires which means that the distance that each rotation travels will be lower than that of the present tires. The number of rotations per mile will, therefore, INCREASE, while the indicated speed will remain the same. Again, actual speed of the vehicle will then be at least closer to speedometer-indicated speed.

Before buying tires, check their circumference in the manufacturer's specifications and compare it to that of the present tires. You say that the speedo is reading about 10% lower that actual speed. If you can find a tire that has a circumference about 10% smaller than that of the present tires, this may correct things nicely.

First, however, I would check the actual versus indicated speed at several indicated speeds. If an indicated speed of 50 is an actual speed of 55 (again, 10% difference), then the tire change is still good. If the indicated speed is 50 and the actual speed is 50, there's something very wrong with the speed-measuring system. But even if the lattter is the case, it's better to be traveling under the indicated speed than over, IMO.

 

Since you bought a used vehicle you cannot really know all the details about the history of the car. The standard tire size for this model is either a 215/70 16 (OEM wheel: 6.5 x 16 ET 38) or a 225/55 18 (OEM wheel: 7 x 18 ET 38) depending on whether it came with 16" or 18" wheels from the factory. As mentioned by Outlaander the circumference of the tire what is needed for the ETACS to display the speed. In the former case it is 2222 mm and for the latter is 2214 mm. As you can see these values are very close. One can also get more or less the same circumference if the car is equipped with tires of 225/50 19 (2223 mm) or 225/60 17 ( 2205 mm) when a 19" or a 17" wheel is used. For 10% error one would need a significantly different set up (e.g. 235/70 18, or 255/70 16; this latter would require custom wheel as it would be dangerous to mount on the stock 6.5" wide wheel anyhow). Since you stated that the tire size is correct (one of the bolded or italics combinations) the only possibility is that the circumference in your ETACS has been altered (either accidentally or because the previous owner had installed a smaller diameter tire and had it reprogrammed). It is also possible that the ETACS has been replaced and a wrong circumference was programmed in.
Solution: Unlike Outlaander I would not advocate for changing the tire size, although I admit it is possible within limits. Here is my reasoning why not. The wheel and tire combination has a relatively small safe and or reasonable range when it comes to mounting, Flexing a tire for a wider wheel or the opposite, putting a wider tire on a narrower wheel is not safe (it is not needed here). If one wants to stay within the safe range one would need to lower the side profile (225/45 18 or 215/55 16 yielding, 2020 mm circumference). Both of these are more expensive tire options and more importantly, they would decrease the ride comfort and would increase the chance to curb the wheels and/or damage the tires (especially if potholes are frequent in your area).
My suggestion is to program the ETACS to the diameter I specified above. There are some of us in this forum, who used one kind of ETACS programming device/program (ETACS Decoder, Diagbox etc.). If I were you I would specify my location and ask whether somebody near you could do this programming. Alternatively, you can go to the nearest dealership and have this done by them. It will likely cost you an hour labor though. Most of us, who opted for our own ETACS programming did it to avoid going to the dealer frequently and get charged (when changing tires (summer, winter) and dealing with TPMS warning). Answering your other question, TPMS sensor cannot cause this speedometer error. Good luck.

 

Thanks for the replies.

I have used a GPS speedo which I previously calibrated from another vehicle I know to be correct +\-2km/h and it is consistently out by 10% at all speeds.

Tyres are the correct stock size. I checked this on the tyre placard and they’re right. It’s running standard 16” Mitsubishi rims. As the tyres are not that old I don’t particularly want to spend $600+ on tyres when not needed.

We don’t get snow here as much so not really needing to swap tyres winter to summer

Im in Australia and not sure if only Mitsubishi dealers would do that kind of editing of the system or if an auto electrical or mechanic would have the know how to do that. I know nothing about editing or programming vehicle settings and didn’t want to order sensors if not needed so might make a few calls to try and find somewhere that can do it. I’m used to speedo cables not electronic ones.