OBD2 scan before buying a used car?

B

bar1

Expert Member
Joined
Sep 15, 2008
Messages
4,402
Reaction score
512
Hi, i am currently looking to buy a second hand car, will an OBD2 scanner help in detecting issues with the car?

where is a good place to get one?
any other tips before getting the car?last time i bought a car was 12 years ago....lol
 
bar1 said:
Hi, i am currently looking to buy a second hand car, will an OBD2 scanner help in detecting issues with the car?

where is a good place to get one?
any other tips before getting the car?last time i bought a car was 12 years ago....lol
Click to expand...

You can buy them online.

It's will only tell you what the dash tells you though. So if there is no error on the dash, you won't find one on the OBD2 scanner. The moment the ECU picks up a problem it will notify you via the dashboard engine fault light. If not, there is no issue :p
 
bar1 said:
Hi, i am currently looking to buy a second hand car, will an OBD2 scanner help in detecting issues with the car?

where is a good place to get one?
any other tips before getting the car?last time i bought a car was 12 years ago....lol
Click to expand...
It might help, but an unscrupulous seller would just clear the error codes anyway. Most obd2 devices can do that.
 
Pitbull said:
You can buy them online.

It's will only tell you what the dash tells you though. So if there is no error on the dash, you won't find one on the OBD2 scanner. The moment the ECU picks up a problem it will notify you via the dashboard engine fault light. If not, there is no issue :p
Click to expand...
But again there are other issues that cannot be picked up by sensors. Honestly imo the best way is to take a trusted friend who is mechanically inclined with you when you inspect and test drive the vehicle.
 
who.dat said:
But again there are other issues that cannot be picked up by sensors. Honestly imo the best way is to take a trusted friend who is mechanically inclined with you when you inspect and test drive the vehicle.
Click to expand...

Agreed. But those issues would not show on the ECU to begin with then.
I agree with you. Get a DEKRA check or something done if you have reservations :)
 
It may help identify issues but as has been mentioned, error codes can be cleared fairly easily.

Pitbull said:
You can buy them online.

It's will only tell you what the dash tells you though. So if there is no error on the dash, you won't find one on the OBD2 scanner. The moment the ECU picks up a problem it will notify you via the dashboard engine fault light. If not, there is no issue :p
Click to expand...

Not necessarily, not all error codes are communicated via the dashboard central cluster, generally only major issues are.
 
OBD2 won't tell you anything unless there's a fault.
Buyer's going to see all sorts of crap he really shouldn't see because the ECU logs things like misfire, so buyer sees the misfire that happened at start on a really cold morning or because the dealer drove the thing with next to no fuel in the tank.. and doesn't buy the vehicle.

The electronics cannot vouch for, or gauge the mechanical condition of the car.
 
Neuk_ said:
It may help identify issues but as has been mentioned, error codes can be cleared fairly easily.



Not necessarily, not all error codes are communicated via the dashboard central cluster, generally only major issues are.
Click to expand...

You might be right :o I have never had to check anything unless the engine light comes on as it will then go to limp mode.

OBD2 scanner can be had easily for around R 1 500. just be very careful. Most sellers don't supply the software and that comes at a separate price. So if you do buy, make sure it has the software.
 
Just realise that OBD2 scanners do not work cars manufactured in SA that were made specifically for our market, as these cars are not OBD2 compliant, despite having a 16 pin OBD2 port - Corsa bakkies, Chev UTE, Polo Vivo, Isuzu bakkies, NP200, Bantams, Nissan hard body etc. Those made for export are compliant.

Ask the guys at www.autotools.co.za for specifics.
 
If I was selling a car I would not allow a non certified person to attach any device to my car. What if you screw it up etc..
 
Pitbull said:
You might be right :eek: I have never had to check anything unless the engine light comes on as it will then go to limp mode.
Click to expand...

As an example, most major issues with result in a CEL or at least an error light like boost pressure not reaching set levels, water or oil temperature going past set maximums or implausible signals from major sensors. Something like a window that no longer goes up or down at a single touch of the button won't result in a CEL or error light but will show up in the error logs when reading the ECU.
 
Any fault code that an ELM327 OBD2 scanner will show you, will activate the 'check engine' light on the dash.

So it's almost pointless buying one if your goal is to check if there are any hidden faults with the car. It will only tell you what the DTC is that is causing the check engine light to go on, and give you live readings from engine sensors.
 
It is possible to disable the Check Engine Light. I test drove a car which went into limp mode - refused to kick down and wouldn’t rev over 3000 rpm - and there was no light on the dashboard.

What I prefer is taking it to the agent while you’re doing a test drive and have them hook it up and tell you if anything looks dodgy. Mostly you’ll have to pay for that, but it’s a small price to pay if you dodge an expensive repair. Last time a bought used, I had at least four cars checked and rejected before I found the one I bought.

Also, the generic code readers will only give you generic information. Most manufacturers have a whole lot of in house codes which give much more detail, and you need different software for each manufacturer to access those codes and settings.
 
These guys have a physical shop and you get good service and info from them.

https://www.electromannsa.com/

Note there are better scan tools and cheap junk.

I recommend you forgo the OBD2 scan and pay a pro to look at the car.
 
I use an ODB2 scanner and my cell phone or laptop when checking any vehicle.
If you are familiar with what these apps can do it will give you a wealth of information.
If the error codes have recently been cleared, it will tell you so and you can ask the dealer why.
I will usually connect the dongle and let it log all parameters while I take the vehicle on a test drive.
If the dealer does not want me to connect, it's easy to walk away.
I'll take that log home and then go through it.
Things like flow rate etc on injectors and O2 sensor readouts can easily show you if something is on its way out.
Also how quickly oil, tranny and coolant heat up can help with underlying issues.
Even input and output shaft speed can show if these are issues with the clutch
The dash display in a vehicle generally only shows you major faults.
 
who.dat said:
But again there are other issues that cannot be picked up by sensors. Honestly imo the best way is to take a trusted friend who is mechanically inclined with you when you inspect and test drive the vehicle.
Click to expand...

Best answer I've read in a while.

Use both, trusted mechanic and the scanner. Perfect piece of mind
 
I am in jhb, looking to buy a Toyota 86.
will the ODB i mentioned above will be able to give me useful information?
 
bar1 said:
I am in jhb, looking to buy a Toyota 86.
will the ODB i mentioned above will be able to give me useful information?
Click to expand...

Nope. Each have different CAN systems.
I could point you in the direction of someone who would be able to help you out. Let me just check if he still has his equipment
 
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X