OBD reader

[mojo]

Hi guys, I'm getting a restricted performance issue on my D4 at the moment and have decided this would be a good time to buy an ODB tool to try and work out what's going on. What is the current recommendation, I remember several years ago being told the IID Tool was the way to go?

[DieselLSE]

Yep. Most go with the Gap IID tool. I use the Nanocom, but if I were to purchase anew, I'd go the GAP.

[mojo]

Ended up getting a cheap reader from Amazon, which diagnosed a MAF / MAP sensor correlation error. Turned out I had a split intercooler hose, which I've now replaced.

Interestingly, I've been driving with the OBD reader, and noticed that the speed it registers is 4 to 5 km/h slower that what the dash says. Do LR deliberately up the dash speed for some reason?

[p38arover]

Interestingly, I've been driving with the OBD reader, and noticed that the speed it registers is 4 to 5 km/h slower that what the dash says. Do LR deliberately up the dash speed for some reason?

All manufacturers do. You’re lucky it’s as low as that. At 110km/h indicated in our past 3 Subarus, the GPS has indicated 100. Ditto in my L322 RR with the Ultraguage connected to the OBD port.

[BradC]

Interestingly, I've been driving with the OBD reader, and noticed that the speed it registers is 4 to 5 km/h slower that what the dash says. Do LR deliberately up the dash speed for some reason?

If you look at ADR 18/03 Clause 5.3 you'll see :

5.3. The speed indicated shall not be less than the true speed of the vehicle. At the test
speeds specified in paragraph 5.2.5. above, there shall be the following relationship
between the speed displayed (V 1 ) and the true speed (V 2 ).
0 ≤ (V 1 - V 2 ) ≤ 0.1 V 2 + 4 km/h

So not less than the true speed + 4Kph and not more than the true speed + 10% + 4Kph. So the indicated speed error must *never* be less than 4Kph regardless of tyre wear, temperature or drivers stomach gas content. It's why I *always* set the cruise control for speed limit + 4 and never get pinged.

[scarry]

One of my brothers has a Mitsy sport,the speedo on it reads around 7.5% more than actual,with OEM tyres.

Not great and can be frustrating for other drivers.

Similar to Brad,i generally set the CC at 105Km/hr,in a 100 zone,and 116 in a 110Km/hr zone and never had a ticket.

Although others still go past me, i think trucks,even B doubles often cruise at an actual of 105,which is around 110Km/hr on the speedo of our vehicle.

[Tins]

It's why I *always* set the cruise control for speed limit + 4 and never get pinged.

It's also why people moan about speeding trucks, when in general modern truck speedos are accurate and the truck is not speeding at all.

0 ≤ (V1 – V2) ≤ 0.1 V2 + 6 km/h for heavy trucks.

[V8Ian]

Very few trucks are good for more than103, these days, the plus 3 is within tolerance.
Modern trucks record and store so much telemetry, that government agencies have access to, roadside. Time and speed are the obvious elements that interest enforcement, leading to situations whereby a driver can be prosecuted for speeding or logbook offences committed weeks previously in another jurisdiction.

[BradC]

It's also why people moan about speeding trucks, when in general modern truck speedos are accurate and the truck is not speeding at all.

0 ≤ (V1 – V2) ≤ 0.1 V2 + 6 km/h for heavy trucks.

I know truck tyres have much deeper thread when new, but that's ****ing insane. I'd say "no wonder people get ****ty with truck drivers" but unless on a steep positive grade I've never seen a truck 6 under the limit ;)