Nissan Patrol 4x4 (Africa)

Hi guys

I was wondering today...

If you were in the market for a 'newish' secondhand car, would the dealers allow you to check the diagnostics of the vehicle you were interested in if you had your own scan tool?

**Specifically the data relating to speed and driving, etc.

I know some vehicles won't store as much data on their OBD as others, however might give some interesting history..

If there is nothing to hide, the dealer shouldn't have any objections at all. You won't destroy anything with checking for fault codes.

Why would a dealer object if not because he knows that something is faulty? At worst after your check he knows if something is wrong with the car which he might not have known before.

I wouldn't buy a second hand car if I wasn't allowed to check the fault codes when asking for it.

Florian320 wrote: ↑25 Nov 2017 15:44 If there is nothing to hide, the dealer shouldn't have any objections at all. You won't destroy anything with checking for fault codes.

Why would a dealer object if not because he knows that something is faulty? At worst after your check he knows if something is wrong with the car which he might not have known before.

I wouldn't buy a second hand car if I wasn't allowed to check the fault codes when asking for it.

Agreed, if there is nothing to hide then what could the problem be?

I would say that, similar to a mechanical inspection or an oil analysis (done at own cost), if the dealer refused, I would walk away, on principle.

Having said that though, if somebody checked my speed data, they probably would not buy any car I was trying to sell...
To be honest, I am not sure what that would tell you about the potential condition of a car. I firmly believe petrol engines should sse, but not exceed their red lines reasonably frequently for good health.

Not while they are cold though, but I doubt that would show up on any scan?

To my mind, the things that kill an engine are:
1) Running on old/dirty/sub-standard oil.
2) Overheating
3) Operating for long periods without decent anti-freeze.
4) Lugging heavily in a low gear (turbo diesels without EGT measurement).
5) Serious over-revving (IE revving to much higher than the red line). In modern engines, this can probably only be acheived by wrong-slotting the gearbox.

Things that prematurely wear an engine are:
1) Heat cycles (IE an engine used only to go to work three blocks away could be tired after 150k km, whereas an identical engine driven by a mining equipment rep may last 500k km.)
2) Working hard while cold.
3) Lugging in a low gear (petrol engines).
4) ...
...
99) Constant operation at or near maximum revs.

Thanks for the replies. I'm pretty interested in buying a OBD tool and will be more than willing to lend it to anyone interested in using it. (next year!!!)

I had typed out a long reply, ranting about a vehicle I had bought and regretted, and then realized that hindsight is... well... hindsight. You live, and you learn!

Rhett wrote: ↑10 Dec 2017 23:56 I had typed out a long reply, ranting about a vehicle I had bought and regretted, and then realized that hindsight is... well... hindsight. You live, and you learn!

We call that "SCHOOL FEES"
I have a Phd thanks to them...