I have an engine warning light illuminated on my MX5.
Fluid levels ok, oil pressure ok, and it's running like a little sewing machine.
So the question is; do the cheap code readers found on eBay work?
I was looking at a MaxiScan, but for under (just) a tenner they seem to good to be true.
I'm just trying to avoid buying stuff only to find that wasn't the problem.
I'm still using the one i bought for £6 off ebay which is going strong and has worked on many cars, just used it on my friend's golf last
week.
What it doesn't do is give you in depth detail, so maybe just an error code eg. P1011 or something like that which you then need to google and
then probably a bit more analysis to work out exactly which component is at fault.
The more expensive ones may give you the specific part, but i think these are many many pounds....
sorry, to add to that - when i had a problem with the zetec on the kit car, it told me a problem with the MAF which i got sorted and all good.
The golf had a problem with misfiring, told us it was a problem on Cylinder 1 but not what, after a bit of a prod realised it was a coilpack, replaced
and car's spot on.
quote:Originally posted by 907
I have an engine warning light illuminated on my MX5.
Fluid levels ok, oil pressure ok, and it's running like a little sewing machine.
So the question is; do the cheap code readers found on eBay work?
I was looking at a MaxiScan, but for under (just) a tenner they seem to good to be true.
I'm just trying to avoid buying stuff only to find that wasn't the problem.
Cheers
Paul G
I think you are probably looking at a knock-of copy of one of the early Autel AL300 series, Autel make good scan tools really best to avoid buying
a knock off as buying one is a gamble.
The current genuine Autel AL319 is a good but very basic scanner for power train fault codes only and can be found for about £25 from UK
suppliers . However a scantool that reads live sensor data is much more useful and one that graphs live data is really useful.
The Autel model I would sugest is the AL519 which sells for about £50 to £60 it won't do Airbags or ABS but it covers live data and graphs
both of which are worth their weight in gold if you have an emisions problem. Launch and Foxwell also do a full range of good scantools from entry
level to almost dealer lever.
quote:Originally posted by pekwah1
quick answer - yes!
I'm still using the one i bought for £6 off ebay which is going strong and has worked on many cars, just used it on my friend's golf last
week.
What it doesn't do is give you in depth detail, so maybe just an error code eg. P1011 or something like that which you then need to google and
then probably a bit more analysis to work out exactly which component is at fault.
The more expensive ones may give you the specific part, but i think these are many many pounds....
Sadly no scantool will give you the specific part :-( most scantools from about £30 will give the code definition eg P0420 = catalyst efficiency low
bank 1 but working on code definitions can lead you astray fault codes are really only the first clue to tracking a fault.
Misfire codes for example P0301 (misfire cylinder #1) quite often point to the wrong cylinder, the misfire could actually be on the nexrt cylinder in
the firing order.
Going just above entry level models a sub £50 scantool will let you read every sensor on the engine most will also let you graph the sensor values
which lets you watch oxygen sensor activity , check the throttle position sensor, MAF grams/sec, watch the misfire counters in real time and much
more.
On cars built since around 2003 most now display Readiness Monitors -- basically the readiness monitors will tell if your car will pass a emissions
test before putting it in for an MOT.
This is a very recentYouTube video from Eric O at the SMA channel showing using live data to diagnose a simple fault and and confirm the repair.
This one from Paul (Scanner) Danner shows using live data for a catalyst fault, really worth watching.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
your best with one which allows you to enter data into the ECU such as injector codes etc rather than just a reader. I have handheld, laptop (wired
dongle) & wireless dongle on an Android tablet, all work very well. Probably the most cost effective is the Android app, you can even use it as a
live engine management dash which looks really cool.
I think you are probably looking at a knock-of copy of one of the early Autel AL300 series, Autel make good scan tools really best to avoid buying
a knock off as buying one is a gamble.
It is a gamble, but the odds are entirely in your favour. I've bought 7 I think, I know of at least 3 other people with one for each car. So
probably about 15 in total, across a range of brands and models. No problems with any of them.
But there is always a risk it's not going to work or does damage.
you've most probably got a sensor fault. My Volvo engine light came on but ran just the same, reader said oxygen sensor 2 heater not reading
(been thrashing the crap out the car at the time so probably got it too hot), many of the sensor have backups so the car will run as normal but they
should be fixed still.
A bit late to this thread, I have a Maxiscan which works fine but is very basic. I also have cheap blue tooth dongle thing which cost about £2 ish of
ebay. I use that with my android phone and Torque light which is very good, free, and also gives live data. I have used it for a few things to monitor
boost, temp and other things to compare to the cars own instruments, interesting to find what the bar graph instruments actually mean. They both work
with OBD II only which officially came in in 2004 but several cars have it fitted before it became a requirement in 2004.
Just a P code without being able to read live data live data makes it very difficult to tell if this a genuine rich condition or a false rich .
A false rich condition can be caused by a faulty O2 sensor but often that would also flag an O2 sensor inactivity code in the ( P0130 to P0135) often
codes relating to air fuel ratio and 02 sensor activity are only triggered after clear once one or two drive cycles are copeted.
Simplest quick test for a common cause of a genuine rich condition is to examine the fuel pressure regulator for a leaking diaphram see this Paul
Scanner Danner YouTube video
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
The usual key to tracking down this kind of fault is to compare the pre-cat oxygen sensor signal output with the post-cat sensor output and force the
fuel lean (create vacuum leak) and rich (add propane to the inlet) and watch how the sensors respond and also watch the fuel trims, but for that you
need to be able to read live data.
As an alternative you can test out the pre-cat sensor with a multimeter start by checking the sensor heater 12v power and ground, disconecting it
checking the sensor heater for continuity and resistance (normal expect about 2.5 to 6 ohms) .
Also with the sensor disconnected check ressistance between the O2 sensor signal output and the heater wires --- this should be infinite.
You can then reconnect the sensor and with engine warm check the voltage between the sensor output terminnal and battery earth. With the engine warm
If the signal from the sensor is rich this wiill be about 0.7 to 1 volt, if it a true rich condiotion and you create a vacuum leak this should fall
below 0.5v , if you have false rich condition caused by a bad sensor or shorted wiring then the voltage will stay above 0.. It isn't uncommon
for the signal from the sensor to the ECU to be shorted to power giving a false rich, the short can be internal to the sensor or wiring which is
exposed to both vibration and heat.
In the oposite case a false lean the sensor is shorted to ground.
This a good Paul Scanner Danner video on a false rich from the pre-cat O2
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
quote:Originally posted by ianhurley20
A bit late to this thread, I have a Maxiscan which works fine but is very basic. I also have cheap blue tooth dongle thing which cost about £2 ish of
ebay. I use that with my android phone and Torque light which is very good, free, and also gives live data. I have used it for a few things to monitor
boost, temp and other things to compare to the cars own instruments, interesting to find what the bar graph instruments actually mean. They both work
with OBD II only which officially came in in 2004 but several cars have it fitted before it became a requirement in 2004.
Torque works and shows a lot of data PIDs but boy is it slow try OBD Car Doctor the graphing is much better (faster) than on Torque. If you try
it and like you can pay for the unlocked pro version.
The graphs that are most useful are the pre-cat (B1S1) sensor and post-cat (B1S2) sensor -- watching the two together will tell you if your cat is
working and if your engine is running rich or lean. The very other useful ones are the MAF airflow grams/sec and short term and long term fuel
trims. Adding together STF and LTF is good way to spot developing faults if the engine is running within limits the result should be less than
+/- 10%, in an engine in a good state of tune the total fuel trim will typically about +/- 3%. even at 100,000 miles plus.
[Edited on 14/6/17 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
