OBD II Scanners And Used Cars

[Hall]

If there is no check engine light can a scan bring up some issues?

I'm sure it's not unheard of for some sellers (private or dealer) to reset the code/light and cross their fingers it takes a while to re-trigger. Some scanners can tell you when it was reset last too.

 

[FSUwelder1212]

I'm sure it's not unheard of for some sellers (private or dealer) to reset the code/light and cross their fingers it takes a while to re-trigger. Some scanners can tell you when it was reset last too.

this is why you always check to see that all the monitors have run. If the code has been cleared it will clear the drive cycle.

 

[Hall]

this is why you always check to see that all the monitors have run.

My comment was more for the average folks who don't take a scanner, but test drive a car and the check engine light isn't on, so they figure things are good. Then it pops up 2 days after they get it home....

 

[javacontour]

Just asking for a friend. If there is no check engine light can a scan bring up some issues?

Yes, you need BOTH no CEL AND all the monitors have completed successfully.
If someone just unhooks the battery, it will take a while for some of the monitors to run. Things like Catalyst efficiency and Evap system monitors only run after some time and if the conditions are right.

 

[javacontour]

Heck, you also need to check that it actually comes on during the "bulb test"
If it doesn't, is the bulb burnt out or similar if it's integrated into the instrument cluster.

 

[BMW Dom]

Yeah, I had a bluetooth obd2 scanner when I bought my car from facebook. There were some codes for things like air mass, misting sensor error, and fuel level issue. It helped me know what I was getting into before I bought it.