OBD2 Port Scanners - What use are they?

sheusz2000

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Fellow Frogger
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Mar 17, 2011
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Newcastle
I'm curious to know what possible use a OBD2 port scanner could be. Apart from diagnostic information, are they particularly useful for a home tinkerer?
 
A obd scanner will only read engine codes and the problem is with cars like your 3008 they can cause gearbox abs and handbrake faults while they are talking to the engine and these normally require a few drive cycles to clear or sometimes need clearing by us. Tinkering with settings isn’t really a thing now because cars like yours are fully loaded and no “Easter eggs” are available like your 307 you could change things add cruise or a CD stacker if you still want something let me know a Delphi ds150e is handy if you have a few cars of different brands I’m not a big fan of diagbox (our dealer tool) clones they are to unstable and things like radios and clusters can be permanently damaged if they cut out during a programming or diagnostic operation.


Garage C5 X7 3008 XTE
Gone but not forgotten 206 GTI 180 306 XR SED 405 MI16 x2 xzara VTS 406 SV 206 XT Berlingo 2011 (best car ever) 306 HDI 307 XSE HDI touring
Fix it right the first time
 
G'day,

I have a Bosch[?] scanner that I grabbed the last time the BA v8 threw a tantrum - it told me nothing, no fault found. Cured by stopping it, waiting 30 seconds, and restarting.... A similar tantrum from the Renault Latitude was cured the same way - but I had to go to the dealer to get all the Christmas tree lights turned off, warranty repair, $75 !! no fault found by all their expensive machinery either, or "experienced mechanics" [?], just a dent in the wallet....

These modern cars are 'puters on wheels, so what do you do when the PC plays up ? You turn it off and start again.... :)

Our local bush mechanic has a much flasher device than my Bosch, he tells me that it rarely gives him answers either. Faults are found the old way - by deduction, experience and replacement or repair. So, I guess the answer is, no, not much use at all.

cheers,
Bob
 
I'm not sure how you'd diagnose that a specific sensor is at fault the old way unless that means trying a known good unit. This is one way I'd imagine a generic scanner might be of use - to POSSIBLY avoid random replacements of sensors on a try it and see basis, which is obviously a benefit for DIY people who don't have such things on the shelf.

I'd imagine that if your scanner says, say, the crank angle sensor is at fault then it's quite possible it's the problem. The issue is though that these scanners usually show other faults as well - I believe this is where expereience comes into play. Where it is the CAS, but this causes other sensors to throw errors, you have to know which are the cause and which are the result.

On saying that, I've only just bought a cheap one ($100) and have limited experience. In my analysis before purchase, I thought it will probably pay for itself - one day.
 
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You are looking at it the wrong way it’s only a guide the old rules still all apply power earth sealing from the first code spitters to the latest stuff that I’ve been paid to work on it’s the same, luckily I was taught to see a code and think what does that sensor actually sense ,let’s say a common one that people throw parts at 02 sensors you could have a vacuum leak a leak in the cat it self like 208s so blocked fuel filters even blocked purged valve or canister, I was shocked at a conversation I was having with a mechanic that rang for advise just last week when I asked him what the long and short term fuel trims are at and his reply was what are they 15 years in the trade.
As I said above unless you have a full function scan tool with access to live data bi directional controls and at least abs airbag and body computer diagnostic you really just have a paper weight you can get a ds150e Delphi for 60 bucks and load it onto a pc and you have 80% of what a dealer can do especially on psa stuff.
Engines electrically don’t really give issues really if you look at most technical posts here they are other car functions.


Garage C5 X7 3008 XTE
Gone but not forgotten 206 GTI 180 306 XR SED 405 MI16 x2 xzara VTS 406 SV 206 XT Berlingo 2011 (best car ever) 306 HDI 307 XSE HDI touring
Fix it right the first time
 
Thanks for the replies. Really interesting, and much as I thought. I work with computers & CNC machinery and have found that, what counts most is not the tool, but understanding what the tool is telling you and the access the tool allows. The problem with a lot of modern systems is what I like to call the issue of cascading errors. The initial problem/fault throws an error, that causes a number of subsequent errors. When looking at the problem I always keep in mind, and train less experienced people to keep in mind, is, what happened first? What changed? What did I do? All too often the focus is on the last observation of an error, rather than the first.

In all fairness, a lot of problems are caused by poorly implemented firmware systems and buggy software. (Don't get me started about my Telstra TV box), where there is not a enough focus on the "what if" scenario.

If you break it down, building firmware systems (the category in which I now place a lot of modern, tech heavy vehicles) isn't complicated. Use a flow chart to proof and error check the system, then write the code. Then you don't have dumb stuff like having your infotainment system playing (and displaying) wrong song titles/track numbers when in album sort mode. Or your blind spot monitor going off when you drive through a puddle of water.

Anyway, the end result is that I think I'll save my money. I'll have a tool that will tell me stuff that I can't do a single thing about. :confused:
 
David, your 'old way' isn't what was meant, I think Bob meant without a scanner at all. That's what I was referrng to when I said I don't know how you'd diagnose a failed CAS (for example) without a scanner. Say, if the car was just turning over and not starting because the CAS had failed. At least the scanner might give you a heads up was my point, in a situation that could be many things (no spark or fuel). I'd hate to have to get my car towed in such circumstances if there might be a chance I could get the car going. Wouldn't this be the only alternative, other than random replacements? Are you saying the generic units are useless for this? Mine's not a complete cheapy but isn't as advanced as the one you recommend either...see link (I got it for $99):

https://www.repco.com.au/en/brands/foxwell/foxwell-obdii-eobd-code-reader/p/A5298839

Of course, I defer to your much greater knowledge and experience with respect (and I'm not being clever either).

I just I wish I'd known about your recommended Delphi unit when I bought my scanner.
 
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No there is a place for those quick scanners just not what I would spend money on. Let’s say you’ve got a cas failed on a RFN 2l but you don’t know that yet . All you really need is 2 test lights one led one standard bulb and a multi meter.
Nnnnnnnnnn no go ah s$&@ dam Peugeot’s
Check fuel at valve in fuel line [emoji106]
Power at coil using standard testlight [emoji106]
Pop the coil out use a bolt or screwdriver to check spark [emoji107]
Check for injector pulse using led test light only[emoji107]
Ok now you’ve got direction
Check the earth return on the sensor [emoji106]
Check the ac output of the sensor no voltage output [emoji107]
You pull out the sensor and find your clutch is failing and bits of your release bearing have taken off the top of your cas 🤮

Or just plug scanner in a dart a crank sensor the problem with this particular problem is that in current data those scanners sometimes shut down while cranking so you can’t see rpm.
And over the years again mostly talking about psa products I don’t tend to see just the egg (sensor) failure you will get ie the clutch has shat and killed the sensor or the bsi is reset and has no data.


Garage C5 X7 3008 XTE
Gone but not forgotten 206 GTI 180 306 XR SED 405 MI16 x2 xzara VTS 406 SV 206 XT Berlingo 2011 (best car ever) 306 HDI 307 XSE HDI touring
Fix it right the first time
 
I've not had much experience with these things but I did have use of a Volvo XC90 that had errors for things that I didn't even know existed.

The local grease monkey, and a family member, both had plug-in OBD2 that blue-toothed to their phones. Fortunately both readings agreed with each other. We just reset the whole lot and concentrated on the ones that came back.

This leads to my second point. Most were probably caused by a failing battery. As has been pointed out above, you have to interpret cascading errors and look at the first one, not the last, and ask did the first cause the second, the second the third, and so on.

I have heard of 15 errors being fixed by a new battery. The errors had devalued the car, so having an OBD2 could simply pay for itself.
 
G'day,

........ Then you don't have dumb stuff like ....... your blind spot monitor going off when you drive through a puddle of water......

you mean it's NOT supposed to do this ? The Latitude does this one all the time - it used to have the blind spot thing a-about, left/right transposed, they fixed that, took all day.

Do I need to whinge about the puddles as well..... ? :crazy:

As to magic boxes, I have a clone CLIP for the Renault, but I'm not game to plug it in until the warranty expires. Also, a ELM327 from a crowd in Sydney for the BA ute that's also waiting to plugged in. Both rely on the availability of a laptop and a steep learning curve - he who dies with the most tools wins I think is the way it works :tongue:

My lack of knowledge in driving these things is tempered by the knowledge that I have the stuff, and whilst it's gonna be a mystery to me, it may help the mechanic out in the bush that's helping me get the car going properly and to turn off all those bloody warning lights. After all, they might be damn good mechanics, but you can't expect these one man shops to have all the special tools for your make/model - like the special spark plug extraction tool kit required for the BA 24v v8, it's not just the froggies that do strange things.

Living in the sticks turns your mind to ways of helping local tradies survive, it's nice to have him around when you need the knowledge.

cheers,
Bob
 
Bob I would plug it in before the warranty runs out and have a play that way they can fix anything you could break.
I’m sure a lot of our customers do.

Garage C5 X7 3008 XTE
Gone but not forgotten 206 GTI 180 306 XR SED 405 MI16 x2 xzara VTS 406 SV 206 XT Berlingo 2011 (best car ever) 306 HDI 307 XSE HDI touring
Fix it right the first time
 
I have heard of 15 errors being fixed by a new battery. The errors had devalued the car, so having an OBD2 could simply pay for itself.

Yes battery voltage is the first part of most diagnosis I’ve had people quote engine computers before checking voltage and change rate.


Garage C5 X7 3008 XTE
Gone but not forgotten 206 GTI 180 306 XR SED 405 MI16 x2 xzara VTS 406 SV 206 XT Berlingo 2011 (best car ever) 306 HDI 307 XSE HDI touring
Fix it right the first time
 
Good info thanks David.

Incidentally, is the LED test light to limit current through the device? Or so it can light on a sniff of voltage and thus instant switching?

BTW I bought the scanner because my son's Clio was randomly off and on going into limp home mode so there was no way narrowing this down (I thought) without some kind of scanner. I was aware the Clio has an ECU loom shorting issue and a throttle pedal potentiometer connector issue, which I thought wouldn't show without Renault specific software. But I thought if I could narrow it down... The alternative was a mobile Renault mechanic (we have a good guy here in WA) but he was flat out.

There were no codes so I presumed it was likely the loom or throttle. Checked loom, could see no damage or obvious issues, so removed throttle pedal loom and tightened the individual connectors in the socket, added conductive grease to each pin - car has now been fine for a month and befire this it had gone limp (!) a few times in a week. So inadvertently it sort of helped, but I probably would have had a crack at the pedal loom anyway before calling out the pros...

I did think afterwards I'd probably wasted $100. It did show a nice smooth and responsive throttle position output trace though!
 
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You use a led low current test light to check switching and to make sure you don’t damage the drivers in the ecu and a high current globe type to check power and earth supplies I even have a headlight globe on some wires with thin pins to load circuits it’s quick and dirty but has worked for me so far in the trade.


Garage C5 X7 3008 XTE
Gone but not forgotten 206 GTI 180 306 XR SED 405 MI16 x2 xzara VTS 406 SV 206 XT Berlingo 2011 (best car ever) 306 HDI 307 XSE HDI touring
Fix it right the first time
 
I have a ScangaugeII in my Canadian market smart cdi diesel. It's great BUT you have to use a "non-CAN" cable with it or weird stuff can happen like the odometer jumping ahead or ESP shooting a code.

Unlike the usual things you can do with a reader, this allows you to monitor boost, fuel consumption, voltage, coolant temperature and much more in real time while driving. It's really quite good.
 
Pity the odometer doesn't jump backwards! They'd sell like hot cakes!

Mine does some real time stuff as well. The graphs are pretty basic, but the numerical data is there as well.

It's very good for my wife's Mondeo and daughter's Astra, probably due to them being newer. There is much more data available.

I should add to the previous post, I was a bit dismissive; it did actually help a lot with my son's car because it gave me reassurance it wasn't likely to be the ECU or many of the other things it could have been (which is what the dash light suggested) and I'd seen online in the multitude of posts about this fault that some in the UK had sourced a new ECU only to still have the issue - some of whom had seen Renault dealers about it! In fact, some had the codes read by a dealer and replaced a number of things which were proved not to be the issue. Apparently the service bulletin fix was to hard wire the throttle loom to the pedal, removing the connector.
 
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