I have a 2001 Chevrolet Prism (AKA Toyota Corolla) and I’m having trouble getting it through inspection. The car passes everything except for the emissions test. The reason I’m given is that my car is failing to communicate with the state inspections machine. It comes up as “OBD Communication Result ? Fail” on the Vehicle Inspection Report.
I had the vapor canister replaced last summer to solve the check engine light/PO440 code problem that seems to be an issue for Prizms. That repair got me through inspection with no other problems last year. Could this be related to my current problem? Perhaps now I have a valve problem?
My mechanic thought it might be a computer or fuse problem and suggested I go to a dealer to get the problem solved. Can anyone shed some light on this? I want to be armed with information. Thank you.
I don’t think it is related to your evaporative (cannister) emissions problem. It is simply saying that when they connect their lead to your connector (under the steering wheel, off to the left or right a little), that it isn’t “hooking up” electrically. It could be something as simple as a bad connecter, bent pin, broken or ground out wire, etc. I’d check your fuses, although I’m not sure if it is fused or not. Then start with a physical check of your connector and trace it back to the PCM, looking for damaged wiring. It could be a PCM problem, but that would be a worst case scenario.
First, treat the communications problem simply as as an electrical problem. It may end up being an engine computer problem; but, you won’t know that until the wiring and connectors are checked out.
The first suspect is the OBD II connector, under the dash, where the scan tool plugs in. Some one may have (unknowingly) enlarged the female terminal for communications, in the connector.
The test station scan tool connector isn’t beyond suspicion. Ask to have another station try to connect (“communicate”).
You need a mechanic who knows, and understands, electrics/electronics/OBD II. Ask around, even ask of mechanics.