OBD Scanner recommendation

colino

You should go on a  UK Juke forum and ask what really works. Some readers can't read Renaults/Nissan at all, others just give the bare bones generic codes that won't help your diagnosis at all. 

AdrianC

colino said:

You should go on a  UK Juke forum and ask what really works. Some readers can't read Renaults/Nissan at all, others just give the bare bones generic codes that won't help your diagnosis at all. 

I suspect ones that don't work at all are either in the hands of people who don't know how to use them, or are OBDII (US) readers that don't cover EOBD (European).

No EOBD reader will give more than the "bare bones generic codes", because that's what precisely what EOBD is. For anything above that, you need manufacturer-specific diagnostics.

colino

Many cheap or unsuitable code readers give simple bare bones generic codes. For example, P0300 is a misfire, a better reader will tell you which cylinder. A P0420 some readers will tell you need a new cat; nothing of the sort, it could just as easily be a pin hole in the exhaust or another dozen faults, which a better, more suited reader will help you with.  No point being the guy with all the gear but no idea. 

Tokmon

fred246 said:

I remember talking to a man who owned a garage. He bought a scanner for £30 and charged customers £70 for 'diagnositics'. He said it was unbelievable the amount of money he had made from it.

A £30 scanner would not be suitable for a garage because it would only give basic engine codes and not diagnose any of the other systems. Plus diagnostics involves more than just reading a code and you often need to do some checking to confirm what the actual fault is. 

I've got some brand specific software for a couple different vehicles and the information that is obtained is far far more than a basic scanner. So any garage that charges £70 for a basic engine code scan and nothing else is pretty dodgy in my opinion. 

AdrianC

colino said:

Many cheap or unsuitable code readers give simple bare bones generic codes. For example, P0300 is a misfire, a better reader will tell you which cylinder.

P0300 is a generic misfire code.
P0301-P0312 tell you which cylinder. (No, I don't know what happens on Bugattis, either)
The code reader will only tell you the codes that the ECU has detected and stored.

If it's not telling you which pot is missing, then perhaps pulling the plugs or injectors would help? Or a compression test?

A P0420 some readers will tell you need a new cat; nothing of the sort, it could just as easily be a pin hole in the exhaust or another dozen faults, which a better, more suited reader will help you with.  No point being the guy with all the gear but no idea. 

P0420 means "bank 1 cat below efficiency". No more, no less. The code is simply telling you that the difference between the pre- and post-cat O2 sensors is not what the ECU would expect from a functioning system. How you interpret that is up to you. If you think the only way you can get a "cat below efficiency" code is for the cat to be knackered, then perhaps it's time to step away from the YouTube tutorials. 

A generic EOBD reader will give you the same EOBD codes as an expensive EOBD reader.
The expensive one may tell you what they mean, but so will a free phone app - and it will almost certainly give you various bits of live data, too. But they're transmitted as part of the EOBD standard, so a £5 eBay bluetooth dongle hooked up to the free software won't give you the live data, but if you pay for the software it will.

The live data alongside the P0420 will tell you what the voltages from the pre- and post-cat lambdas are, and that may help. But physically checking the exhaust for leaks will tell you whether it could be false oxygen, and shoving an external gas analyser up there will tell you if it's a dead sensor or a duff cat.

The difference comes outside of the powertrain EOBD codes, and that's all manufacturer-specific. EOBD doesn't pretend to give you ABS codes or HVAC or...

colino

A cheap/unsuited code reader will absolutely not be able to read the codes from every car, no matter what Google tells you. 

AdrianC

colino said:

A cheap/unsuited code reader will absolutely not be able to read the codes from every car, no matter what Google tells you. 

If you buy an OBDII one, probably true.
But EOBD is EOBD is EOBD. And every car sold new in the UK since 2001(p)/2003(d) must, by law, have EOBD diagnostics.

tedted

no colino is right wether its obd or eobd the cheap ones cannot intergrate with a lot of modules found in modern cars

AdrianC

tedted said:

no colino is right wether its obd or eobd the cheap ones cannot intergrate with a lot of modules found in modern cars

That's right. Because both OBDII and EOBD are powertrain only.

Everything on top is manufacturer-specific.