Thread: road speed hi

Originally Posted by thai_tiger

Had the nanocom connected today on instrument page and noticed that road speed is reading approx 7kph faster than actual speed. Is this normal and will it effect other setting ie anything speed related.

Just packing the truck up ready for a long weekend away in Geraldton, first time away for a long time.

Speed ratio is adjustable in Nanocom to cater for different tyre sizes etc. From memory it is in the last screen under instrument mode setup, along with setable coolant temperature alarm. I set my temp higher than most (who do about 95/100) at 105 cos I do some heavy towing.

Edit - speedo reading wont affect any other aspects except km driven.
Re temp - TD5 is good for 120 degrees coolant

The question is that it's a nanocom glitch or the VSS delivered by the SLABS is wrong cos then it can mix up things a bit as it's part of the management... especially on autos

though i think it's something with nanocom's software cos mine reads also around 6kph higher as well while i compared with hawkeye which was accurate.

Originally Posted by ENGINE MANAGEMENT SYSTEM - TD5

Vehicle Speed Signal (VSS)
The VSS is an integral part of the ECM's overall adaptive strategy. The ECM receives the signal direct from the
SLABS ECU. The SLABS ECU is not connected to the controller area network (CAN) so therefore is hard wired.
Vehicles fitted with automatic transmission have two vehicle speed input signals to the ECM. One signal is from the
SLABS ECU and the other is from the automatic transmission ECU. The ECU compares these speed signals.

You most likely will find the ratio is set to 1.2 on Nanocom. Mine has always been out until I fitted the 1.4 ratio transfer case with 32" tyres then it was spot on, even though Nanocom said 1.2. I now have a 1.2 ratio TC, 3.8 ratio diffs and 265 75 R16 (32") tyres and Nanocom read perfect again. (Still set to 1.2)

In my case the speedo on the dash is out by about 9-10%, but the Nanocom reading is true.

As standard the speedo is correct but Nanocom is out, just as you describe.

Go to the right most page in instrument mode. Hit setup.
Change the default of 1.1 or 1.2 to 1.0.
Relax in speedo == nanocom instrument speed.

Do same and set to 1.1 to take account of 10% oversize tyres and enjoy nancom telling you the actual speed while the speedo is off by that 10%.

I have no idea why it seems nancom comes with a ratio of something other than 1 by default, perhaps some kind of test process before shipping.

Double check using a GPS navigation device.

The previous owner fitted 275 x 16 x 70 tyres to my D2 and the speedo reads 92 kph when the GPS says 100 kph. So does most of the other traffic on the freeway. May be I should have a look with the Nancom as well. I'll go back to standard fitting tyres when these wear out.

It's illegal for the speedo to read less than the actual speed, so the speedo is always set a bit higher, I believe.

I need to have a fiddle with my Nanocom then both it a the speedo are not accurate, will try these changes. Thanks

My Defender when the speedo reads 100 is doing about 96.