Diagnostic scanners.

gazzat22, Apr 9, 2:27pm
Have been told these wont show anything unless there is a Fault symbol or code showing,Is this correct .I thought the computer would hold Fault codes.
peja, Apr 9, 2:35pm
I believe it depends on the car, newer cars have memory in which the codes are stored and can be read, older ones dont. There are a couple of experts on these in this forum though, so I would bow to their superior expertise on this
intrade, Apr 9, 2:38pm
well that depends , i can tell you you where wrongly informed.
its not as straight forward to explain,
diagnostic scanners and code readers and professional tools
are all different things .
now to that symbol i would guess you mean the check engine light.
the light stays on if there is a permanent fault detected one that is not intermittend , there can be heaps wrong with a car and a ton of codes stored and no check engine light is on because its not a permanent occuring fault.
also there is 2 rooms global obd2 and the other room is oem manufacturer code room.
to read the oem codes out you need a oem capable scanner with software to interpret the codes meaning correctly.
intrade, Apr 9, 2:45pm
be intresting to know who told you that poster 1
and what car year model make engine gearbox are we talking about here?
bigfatmat1, Apr 9, 2:48pm
Fault codes can be stored and no light on dash quite common to read a stack of faults codes out of a vehicle with no light on dash depends on manafacturer, programming of software,occurrence and importance.
gazzat22, Apr 9, 3:00pm
OK intrade, a 2005 mazda 2 /demio light,came on in neighbours car,his son disconnected battery,light went off neighbour took car to 2 local mechanics who both told him same story.WAit till light comes on again?
intrade, Apr 9, 3:17pm
i hope they did not erase the codes,
and you know these 2 mechanics are morons whom i would not let near the car if i was him.
Disconecting the battry is also a moronic idea. you know some cars wont even start if you do that sort of thing because the battery capacity needs to be programmed to the computer.
Disconnect battery is 90s mitsubishi stuff to reset the codes storage , it was never a good idea at all to do that in any case
But a 2005 wont have lost any codes by disconecting the battery.
bigfatmat1, Apr 9, 3:32pm
You are jumping to conclusions. The mechanics may not be morons quite often in a case of customer been doing things ie disconnecting battery/fidling googling. It would be common practice to note codes, clear codes, if fault cannot be recreated or is very intermittent send customer off. When they return they could re read codes and diagnose from there instead of being led down a garden path by a fault the customer has induced!
bigfatmat1, Apr 9, 4:03pm
That is of course providing there is nothing obviously wrong via a quick inspection
gazzat22, Apr 9, 6:02pm
The 2 mechanics he went to told him because the fault light-an engine symbol wasnt there there wasnt anything to check so he would have to wait till it came on again and take it in again.there doesnt appear to be anything wrong and the vehicle is going well so will have to wait and see.
intrade, Apr 9, 6:37pm
if that is what happened then i stand by it a bunch of mrons with no clue what so ever.
A 2005 car you dont wait till the light is lit it could mean the difference between a few hundred $ to be spent now and tousends when the light comes on permanent and it is broken down on the side of the road.
i dont know how good bosch is on mazda but i would say he should take it to supersheep and pay for the full scan and then you can post what the codes are we can then figure out how urgent a repair would be required and what causes the codes could be.
you need freezframe data and all codes printed out .
http://www.supercheapauto.co.nz/vehicle-diagnostics/home.aspx
tweake, Apr 9, 7:20pm
i agree, they should have check the codes then and there. most newer ecu's don't loose codes due to power failure.
also that would prevent the other issue of them reading very old codes.
bigfatmat1, Apr 9, 7:36pm
Again jumping to conclusions Have a 07 demio in at work codes cleared when batt went flat. So mechanics prob didnt see any codes. We dont know the full story so best not to call mechanics morons when they are the inocent party
bigfatmat1, Apr 9, 7:37pm
once codes are cleared they are cleared including history codes! the only way you can see history codes on a mazda is if someone has not cleared them. disconnecting battery does not clear the KAM on a mazda however this needs to be cleared with a diag tool
tweake, Apr 9, 7:43pm
exactly. can be hard to diagnose when its full of old codes.
so they need to be cleared so you can work out which codes relate to the current problem.
gazzat22, Apr 10, 7:29am
So what you,re saying is that although the light is out and the car is going ok it should be taken to lets say a Mazda dealer to be checked I,ll tell him but i can imagine what he wiil say.!
intrade, Apr 10, 7:50am
is this guy a mazda dealer ? read the other thread about this subject i just wrote exactly wha you dont whipe codes and why you then still would in enough understandable details i hope.
intrade, Apr 10, 8:10am
the car should be taken to a oem level diagnostic tool for a fully scan
i do a full scan on any vehicle i service and tell clients if there is problems and if the problems should be adressed urgantly or not
thats how its done professionally i recon.
quote
I,ll tell him but i can imagine what he wiil say
so you think you know that he is a moron? think of it why would you have a moron try and fix your car it dont make sense find a better place
like this guy from burger motor i seen him now on 3 courses that i have taken at least they have staff who get up to speed with how it really works. Be warned even main dealers can be morons , the problem is deep and originates from manufacturer of cars who prevented mechanics to learn how it works for real and just had them swap stuff and follow flow charts , this worked on older cars quite well where there was limmeted stuff to swap out and not 100s of computers linked with each other to start compensate for a fault a other computer has detected like modern cars do to meet the tuff emission laws.

i dont know if that was venturing to far that its not understandable now?

i need to know how much people understand as i will be making information pages for my website for normal people to try and tell em the truth in simple form. = quite a difficult task when only about 2% of the world in the diy mechanics know how it realy all suposedly works.
gazzat22, Apr 10, 10:46am
Right,i will suggest he takes the vehicle to a Mazda dealer or an auto electrician who has the proper gear but its up to him,
mechnificent, Apr 11, 6:21am
Trouble codes get set when a problem has occurred several times. They ignore one-off cases of missed/incorrect signal. For a code to be set it takes between two and in some cases six instances of an intermittent problem occurring.
The dealers though can put the cars into "diagnostic mode" and take them for a drive and if the problem occurs even once in that mode a code gets set. So the dealers can find intermittent faults way quicker, and test them afterwards with greater confidence, than most garages.
gazzat22, Apr 11, 8:03am
Thanks for that an understandable answer at last !
evo_spares, Apr 11, 8:22am
Correct, some (not all) DTC's require a set number of faults over a set number of drive cycles. However most JOBD compliant vehicles have the ability to store provisional DTC's which are DTC's that may not have reached the number of faults or drive cycles to activate the MIL (good software will have the ability to read provisional DTC's as its stored in a differant lookup address) but cheap tools wont be able to access them. There is also check mode for JOBD compliant vehicles which will increase the sensitivity of DTC judgement threshold
zephyrheaven, Mar 19, 4:57am
Im offensive & I find this thread moron