I got TJ Magna, speedo an odo are out about 5%.
I reckon the trip computer is out also, distance to work reads 21.5km, other cars show 19km which is spot on. this is the 2nd magna i've had thats had the same problem.
Been thru various speed checks 105 reads 100 car has standard tyres no mods what so ever.
I know most cars are out, but not 5% i think for a 2002 car this is pathetic.
I guess my question is can this problem be corrected easily without going back to a dealer.

Nope, its not calibratable.

I am just assuming here, but the ECU just takes a VSS (vehical speed sensor) input for every rotation of the driveshafts and converts it within set firmware in the ECU.

Or even worse it is cable still like a ghetto datsun 120y?


Your only option is to change cogs within the VSS setup or cable setup.




I have never seen a magna speedo setup, but if it is anything like 99% of other cars that is the exact way it will be.

im pretty sure it gets readings from gear box speed sensor

what abt this jaycar kit will it work?

http://www.jaycar.com.au/productView.asp?ID=KC5435&CATID=&keywords=kc%2D5435&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=

speedo is a good thing if it read 105 on the speedo and it checks at 100 on the radar

odo is a bit strange but having overinfladed tyres and cause that much difference over a distance


i would say %5 is pretty good

does the trip computer match the dash reading ?

I think it would work.

The VSS is generally just a reed switch every rotation of the wheel. The ECU then checks for rate of change and rate, and outputs to the speedo accordingly.

my standard speedo reads 113kph if I am actually doing 100kph. thats 13% out

By coincidence happened to be today’s article

http://autospeed.drive.com.au/cms/A_108262/article.html

hey all, just spent yesterday in the pouring rain to install this jaycar kit in the 380. the speedo was out, probably made worse by the new rims. i couldnt get the speedo wire on the 380 cause its all multiplexed, so i thought id be smart and tap into the vehicle speed sensor.

rigged up a harness plugged it all in and away it went! calibrated with the GPS got it reading 100 dead on 100. yeah! just got to tidy up a few wires and secure it in.

then i noticed the tranny was shifting funny, it was really clunky :( not good. driving along and then CLUNK! the check engine light came on the netral light started flashing and the tranny locked in 3rd :( not happy.

ripped it all out and the problems went away, exect the speedo is back to telling fairytales.

now to go sheepishly back to the dealer to get the light reset :rant:

moral of the story : cant get it to work on a 380. but on the magna there is a dedicated speedo wire so it will work

I got TJ Magna, speedo an odo are out about 5%.
I reckon the trip computer is out also, distance to work reads 21.5km, other cars show 19km which is spot on. this is the 2nd magna i've had thats had the same problem.
Been thru various speed checks 105 reads 100 car has standard tyres no mods what so ever.
I know most cars are out, but not 5% i think for a 2002 car this is pathetic.
I guess my question is can this problem be corrected easily without going back to a dealer.
Every magna i've owned or driven has done the exact same thing, 5% out. It's been designed that way to allow some leway with speeding. I usually sit on about 5 over the limit, makes me feel like i'm being a rebel, but at the same time i'm actually doing the limit :cool: .