Originally Posted by blackfang
Ok and? I have serviced several cars with the CEL on and guess what? It wasn't an 02 causing it. That CEL will stay on until the ecu reconized a change in the parameter of that DTC. Just because yours was an 02 related, doesn't mean they all are. There are several different DTC's both emissions and non emissions related. Hell she can have a transmission issues(automatics) that can throw a code.
I had a kid bring in his v6 Mustang with a cel on for a month. What did I find? Maf was dirty, TPS sensor wasn't fully plugged in and the air vent hose on the drivers side valve cover was loose.
Only if you tighten it. If you leave it loose the ECU will reconized it is not pressurized and it will stay on. That is why many auto manufacturers have the EVAP system. I see this alot at the dealership as well.
Not really. A dirty Maf can throw this and you wont see a decrease in performance, same with the Secondary air injection system on the engine as well, you won't see any chance in performance, Along with the EVAP system and the valve and charcoal canister, ECT sensor can do this, IAT sensor can, even the VSS can have a fault, catalyst below efficiency(converters).I can go on and on, but don't assume it's tyhe 02's because no change of performance will only be associated with the 02's
Again, I just showed you what some of the issues are that can behave correctly that I have found on cars that were not 02 related.
Again, I wouldnt listen to this guy as I have seen people follow that guidance, and I handed them a bigger bill for something they could have fixed sooner. Look at it and you KNOW what it is. It could be anything, and that is why they created the OBD II
The MAF can be leaned with computer contact cleaner, and isn't that big of a deal, neither is the tps sensor not being fully plugged in and the air vent hose being lose. all of that took what, 10 minutes? And the shop (of course) charged an HOUR of service.
Most of the time a dirty MAF will show driveability issues, AND rarely shows up on the CEL, since the computer doesn't know anything's wrong (it's an incorrect reading). ECT and IAT will also have driveability issues.
You are correct, the VSS WON'T show driveability issues, but it's highly unlikely on a 40,000 mile car, unless there's something upstream, which WILL show up in driveability.
I'm not saying anyone shouldn't get it checked out, but I am saying it's probably nothing to panic or otherwise worry about.
Woe to him who builds his palace by unrighteousness,his upper rooms by injustice,making his countrymen work for nothing...Does it make you a king to have more and more cedar?Did not your father have food and drink?He did what was right and just,so all went well with him. He defended the cause of the poor and needy,and so all went well...But your eyes and your heart are set only on dishonest gain,on shedding innocent blood and on oppression and extortion. Jer 22:13, 15-17