Bought my son a 99 sl. He's been trying to get it licensed and can't get it to pass emissions. I doesn't fail. It reports back "not ready" on most of the sensors. The mechanics we've seen so far said it's like the battery has been replaced or the computer has been reset, which is not the case. Has anyone else run into this and what needs to be done to fix it?

 

DO any diag codes come up at all (Pxxx) ? ( Just asking to be thorough)
An ODBII car will indeed fail inspection (here in NJ anyway) if too many "Not Readys come up when they scan the diag port under the dash.

The mechanic is maybe on target with the "computer has been reset" comment in the sense that it is behaving as if someone has cleared a bunch of codes recently, which sets most of the diag statuses in the computer to "Not Ready"

My guess is the previous owner cleared all the codes right before you purchased it so that you would not see the service engine soon (SES) light come on, indicating codes stored in the computer.

There are various drive cycles that must be completed before the car's computer can determine if the different systems (emissions for example) are operating properly.

My guess is that the SES will illuminate shortly......

Hope I'm wrong.....