RAV4 Speedometer inaccurate

[Talbit]

I started this post a few days ago but it seems to have disappeared.

I’ve got a 2.2l diesel GXL RAV4 (built June 2013) and the
speedometer reads 6klm/hr higher than the true speed as measured on two independent
GPS navigators. It’s 6klm high at 60klm/hr and 80klm/hr so it appears to be an
offset not a percentage error. So to travel at a true speed of 80klm/hr I need
to go at a speed that shows 86klm/hr on the speedo. I know speedos are set to
read higher than the true speed – I don’t know why – but this is too high. What’s
the use of a speedo if it doesn’t read the correct speed? Surely these days it
shouldn’t be too hard to get it right. Has anyone else noticed or is it just
me?

Regards

Talbit

[Hiro]

I started this post a few days ago but it seems to have disappeared.

I’ve got a 2.2l diesel GXL RAV4 (built June 2013) and the

speedometer reads 6klm/hr higher than the true speed as measured on two independent

GPS navigators. It’s 6klm high at 60klm/hr and 80klm/hr so it appears to be an

offset not a percentage error. So to travel at a true speed of 80klm/hr I need

to go at a speed that shows 86klm/hr on the speedo. I know speedos are set to

read higher than the true speed – I don’t know why – but this is too high. What’s

the use of a speedo if it doesn’t read the correct speed? Surely these days it

shouldn’t be too hard to get it right. Has anyone else noticed or is it just

me?

Regards

Talbit

According to ADR 18/03, as of 2006/2007 all new cars sold in Australia must have a speedometer which reads safe (ie reads greater than actual road speed) and must not indicate a speed greater than 110% +4km/h of actual road speed (ie at an actual road speed of 100km/h the speedo can show up to 114km/h).

According to the numbers you gave, your speedo meets this regulation and thus is not faulty or illegal. The reasoning behind the regulation is to allow for differences in temperature, tyre inflation pressure, tyre wear, tyre size, load-capacity as well as manufacturing tolerances in the speed sensor and speedometer itself, as well as to remove a legal loophole that allowed people to exceed the speed limit despite their speedometer showing a speed lower than the limit.

In short, you're in the exact same boat as every other new car driver out there. Doesn't matter if you're in a Rav4, Commodore, Ferrari or Great Wall, your speedo could be reading the same way.

[Altezza]

My 2000 Avalon and my 2013 Camry Atara SL are both about 6% “fast” as well.

[Talbit]

Thanks gents. But it's damned annoying!

Talbit

[Hiro]

Thanks gents. But it's damned annoying!

Talbit

Why is it annoying? If you're getting annoyed with doing the indicated speed limit and are constantly being overtaken/tail-gated, there's a decent chance that it isn't that the other cars have more accurate speedos, rather that they are speeding.

[Talbit]

Can anyone tell me how the signal gets to the speedo. Is it via a signal wire or is it via CAN bus?

Talbit

[helijohn]

Thanks gents. But it's damned annoying!

Talbit

I agree. My '96 runs 10mph fast at 70mph. In other words when it says 70 I am doing 60. This is crazy. It means oil changes and so on come up early. I can go up a few tyre sizes to compensate and think I have got it worked out what size to go to next to bring the discrepancy down to a reasonable level.

[Hiro]

Thanks gents. But it's damned annoying!

Talbit

I agree. My '96 runs 10mph fast at 70mph. In other words when it says 70 I am doing 60. This is crazy. It means oil changes and so on come up early. I can go up a few tyre sizes to compensate and think I have got it worked out what size to go to next to bring the discrepancy down to a reasonable level.

You might find that the speedometer accuracy is different to the odometer accuracy. Here in Aus the speedo can be out +0 -10%, but odometer accuracy has to be +-4%, much stricter. I've seen mention in some places that this no longer applies after 2006 because odometers are apparently no longer legally required (or maybe because 99% of them are now digital), but it will still work for the bulk of new-ish cars on our roads (obviously can't comment on your situation since you don't live in Australia)

[helijohn]

after 2006 because odometers are apparently no longer legally required (or maybe because 99% of them are now digital), but it will still work for the bulk of new-ish cars on our roads (obviously can't comment on your situation since you don't live in Australia)

I can't imagine what I'd do without an odometer - it is so important. When I get bored on a long trip I often check how accurate it is by the marker posts on motorways. :D :D

[helijohn]

Right, I was running 10mph fast so I went up a few tyre sizes (width and aspect) and now the speedometer reads only 4mph fast. Big improvement.

[Talbit]

10 mph over is a big error. Even 4mph over is too high I recon. That's about 6.4 klm high. I recon we should be able to tell the car what the tyre sizes are and they computer should adjust to suit. Anyway, it's no use whinging. We are stuck with it.

Again, my 2000 Camry is spot on while the RAV4 is 6klm over. The sooner we go by GPS the better !!!

Talbit

[Hiro]

The sooner we go by GPS the better !!!

And what happens in tunnels/around skyscrapers etc? Especially with the number of speed cameras in NSW tunnels (Harbour, Lane Cove etc), relying on a GPS speedo (these already exist by the way, Speedhut make them, mostly for retro-fitting into old-skool cars without needing to interface with the original mechanical speedo sender) is just asking to be fined for speeding...

[helijohn]

The sooner we go by GPS the better !!!

And what happens in tunnels/around skyscrapers etc? Especially with the number of speed cameras in NSW tunnels (Harbour, Lane Cove etc), relying on a GPS speedo (these already exist by the way, Speedhut make them, mostly for retro-fitting into old-skool cars without needing to interface with the original mechanical speedo sender) is just asking to be fined for speeding...

There are some people who pretty much drive by GPS for one reason or another!! Nudge nudge, wink wink, know what I mean, know what I mean!! ;) :D

[Talbit]

Well Toyota are not going to budge.

They say it's within specs (which if you go by the design rules, it is).

I recon it's an entry in the computer, i.e. it gets a speed pulse from the gearbox or wherever it gets its reading and multiplies it by a set amount - the "K" factor - so if you know where to find it then it would be a matter of changing the "K" factor and all would be okay. So who out there knows how to do it ?

As for GPS, I guess if you lose GPS lock then it's a matter of going by the speedo reading and that would keep you below the limit. Then if you wanted to mentally add the "K" factor then you could be spot on. But it's adding the error mentally that is the problem.

Talbit

Edited June 17, 2014 by Talbit

[Altezza]

Hi Trevor. I had the same problem with Toyota and my Avalon. They would do nothing for me. I do know at one stage they were replacing "wheel speed sensors" but not for long. After about 3 letters to Toyota head Office I gave up. Our new Atars Sl speedo is also "fast" by about 6%. Colin

[Talbit]

Colin,

Did Toyota head office respond at all?

I suppose you've looked back to the post that talks about the Australian Design rules. 6% is within that range so I don't think we are going to get it adjusted.

I think I'll try an experiment. I might go into a dealer and say I want to by a new car and say that I've heard that the speedos read incorrectly. I recon the saleman will say that it can be adjusted. Shows I've go too much time on my hands!

I'm also having problems with my new RAV4's oil consumption. Look here..

http://au.toyotaownersclub.com/forums/topic/37242-oil-consumption/?view=getnewpost

The local dealer says there is nothing wrong.

Might be time do get out the pitch forks and march down the main street!

Talbit

[Hiro]

I think I'll try an experiment. I might go into a dealer and say I want to by a new car and say that I've heard that the speedos read incorrectly. I recon the saleman will say that it can be adjusted. Shows I've go too much time on my hands!

No, they'll say that the speedo reading meets ADRs - why would a salesman admit that their product is "faulty" (by your logic, not the law) and can be adjusted by the user (which would probably void warranty too)?

[Talbit]

No, I recon the salesman would say that the speedo can be adjusted by them just to get the sale.

[helijohn]

10 mph over is a big error. Even 4mph over is too high I recon.

Talbit

I am just about OK with 4mph over.

I find myself doing a quick subtraction all the time. It is too distracting. Like today I went past a speed sentry and it told me I was doing 28mph when my clock was showing about 34. I need to see that I am doing 30 when I am actually doing 30 so I can drop below it in 30mph limits.

My Pajero is bang on, why can't Toyotas be too??

[Andrew162]

My Celica has undergone various changes in the time I've owned it... from 14x6" wheels (195/60 rubber) to 15x6" (205/50), then to 16x7" (205/45). Also swapping over the stock 1st gen 3S-GE + box for an ST202 unit and it's box. I'm quite surprised that the speedo isn't further out than the 10% it is now. I'm good with instant mental math calculations so it doesn't bother me as much as it did originally.