If the front signals and the rear signals look identical, the catalyst is not doing its job. Sponsored by AP Emissions.
If you are the kind of technician who solves emission codes by replacing parts and hoping the check engine light does not come back on, this article is not for you. But, if you want to diagnose a emissions-related problem, confirm the fix, and know when the car leaves the shop the job will be completed, this article is for you.
A moral dilemma that many shops encounter on a regular basis: A good customer comes in with the engine light ablaze. Running the usual diagnostics, you encounter a catalytic converter efficiency code, a slow to respond oxygen sensor or some proprietary fuel trim code. Other than the light, the customer has not noticed any other