Incorrect speedometer reading

[07 G35 Sporter]

Hello forum

Just registered since I am a brand new G owner. Love my ride so far except. The speedo is reading 7-8 km/h faster than actual speed.

Eg. Speedo says 120km/h - GPS says 111km/h.

With all speeds...doesn't matter. Tires and rims are still factory (correct size).

Any thoughts to this. Warranty is up as of Nov 31/10 and I need to get this fixed ASAP.

G35 Sporter

[telcoman]

Hello forum

Just registered since I am a brand new G owner. Love my ride so far except. The speedo is reading 7-8 km/h faster than actual speed.

Eg. Speedo says 120km/h - GPS says 111km/h.

With all speeds...doesn't matter. Tires and rims are still factory (correct size).

Any thoughts to this. Warranty is up as of Nov 31/10 and I need to get this fixed ASAP.

G35 Sporter

I've noticed the same thing between my speedometer and my Garmin GPS
The difference could save you from a speeding ticket

Telcoman

[SVTCOBRA]

Welcome to Nico!!

As cars get older, the speedo can get off.
My daughter's 00 Max is about 10% off. We got it tested after her second speeding ticket!
She now adjusts her driving based on that.
She has 100K miles, how many do you have?
You might want to get it checked to know exactly how much it's off.
I really don't think there is a way to fix it....other than compensating with different diam. tires.

[07 G35 Sporter]

It only has 56,000 km. I really don't think it should be out at all. Checked Garmin speed against cell phone app and sisters 06' Montana. All three read 100 bang on. Get in my car and GPS reads 92-93 while speedo locked on at 100. Obviously a problem.

There must be a way to calibrate this issue at Infiniti. Going in today.

[SVTCOBRA]

Good luck!
Post what they tell you!
I was told by Nissan that there was nothing they could do.

[370Z/28]

Any possibility that the original owner could have changed the gear? I would think it would make a lot more of an inconsistancy though.

My knowledge is more American Muscle than G so I'm sure I'm not much help, but when I changed my rear end in my Camaro, I bought a programmer from Hypertech to recalibrate the speedometer.

[07 G35 Sporter]

So I took my car to Infiniti today to get a window leak repaired...done - but now have a film on the door. Gonna take a pic before I wash it in case it doesn't come off.

Speedo issue - Showed the service technician the video I took of both cars speedos and GPS's and the he said that doesn't prove anything. HUH !! He then said what website did you get that from? HUH HUH !!!!

I said what are you talking about website. Explained to him again what I did and after 5 minutes of repeating and showing him the video three times he finally got it. Anyway after that they couldn't really do anything except change the speedo. Doing it next week.

The service manager said that Nissan is known for their speedos being incorrect. Sure 1-2 maybe, not 7-9. C'mon.

Keep you posted.

[kboy79]

My G35 doesn't have this problem, but I have been complaining for years to the dealer regarding my wife's FX. They say no problems that they noticed, yeah right.

About a month ago, we get a letter from Infiniti regarding a national recall for the FX saying the speedometer is about 5 miles off. They said that they will fix the speedometer and the additinonal mileage that was accrued due to incorrect speed.

Lame...

[audtatious]

I'll have to check it out. Last time I checked the GPS and speedo were 100% in tune with each other. That was when the car was new so I'll have to see what it shows after 36k.

[07 G35 Sporter]

Okay, it's been a while but I have news regarding the speedo issue.

It went in to be repaired (new speedo). Took 2 1/2 hours, but they said they put a new one in. Great - problem solved. Get in, drive away, get on the highway and set the cruise for 100km/h. Turn GPS on and what does it say? 92km/h. WTF.

Had an appt. so I couldn't turn around and go back. Called the next day and the service dept. said they would look into it. Bring it back next week. Next week comes and once again I drive just over an hour to get this issue fixed. Once there and after looking at it they say, that they replaced it with a new one and there is nothing more they can do. Excuse me! I stood my ground and demanded it be fixed. Sure enough the car goes out for a drive. Five minutes later the technician comes over and says "Yep it's 9km out" No kidding, really. They have to make a call and won't get the info until the next day.

Next day arrives and I get the call. They put the old style speedo in. The new style has been ordered. A week later - drive back...again....total trips 6. New speedo in, drive away and voila - - fixed. This could have been done 5 trips ago if they listened and payed attention.

Now I have to deal with the heated seats not working properlly and fighting for that. Back not heating up and the whole driver seat takes 30 - 40 min to heat up. They said there is current going through so there is no problem, not to mention the expense of replacing the whole seat. Yes there is, it's not working "properlly."

Keep you posted once again. Corporate will be getting a call on this one.

[GAU-8]

I have a similar issue on my '06 sedan with 33000 miles. street speeds here are 45 typically. My car says 45 on speedo. GPS on Garmin and iPhone 41. Get on the freeway. 65 on the freeway. Speedo says 65 but GPS and iPhone say 61. I know that's the opposite of your issue, but my worry is being the clog in traffic. I hate following the slow guy. Turns out I'm the slow guy. Factory 17's with 215/55/17 factory recommended rubber with plenty of life in them (10/32-11/32). Never thought to bring it up with the dealership. They're just as stupid as the guys the OP had to deal with.

[07 G35 Sporter]

No no. That's pretty much what mine was doing. speedo read faster than my actual speed. I doubt very much you have any warranty left to address this issue, If it's that much of a bother you should at least check the cost of replacing it.

No harm in inquiring.

[GAU-8]

Oh, I see. I have extended warranty on the car so I might make a complaint and see what they say. Worst they can do is say no. Only other alternative is do the math to get the right circumference tire to make the adjustment. Wider tire with same sidewall series should increase the diameter overall.

[RichardnVA]

I drove by a roadside speed trap with the radar gun that displays your speed, and my speedo was higher than the radar gun. I love gps but I question their precision for determing actual speed. I would check the owners manual. I bet theres some wiggle room posted in the gps manual about precise speed, maybe + \ - 5 or 10%?

The best way that I know of is to get on a highway with posted mileage markers every mile. Get your speed up to 60 and set the cruise control. Then time how long it takes you to drive a mile by using the mileage markers to determine your start/stop timing marks. It should take exactly one minute to go one mile. I usually do it two or thee time trials to account for adjustments in terrain, elevation, or minor mistakes in either my stopwatch starts/stops or slight inaccuracies in the mileage markers. I'm sure the gps way is pretty accurate, but this way works for sure.

[leeG35]

GPS is just as accurate as a measured mile with a stopwatch as long as you drive at a constant speed for 15 or 20 seconds.

Even a calibrated speedometer can give false reading if you are accelerating or decelerating. The speed measuring system needs some small time to stabilize.