A vehicle can fail an emissions test if the inspector notices smoke coming from the crankcase or tailpipe. This can occur while the vehicle is idling and/or at 2500 RPM. While conducting the emissions test, observe the exhaust in the rearview mirror and check for smoke. Do not consider smoke coming from any other area besides the crankcase and/or tailpipe.
An oil leak can cause smoke from the engine bay. If oil drips onto a hot element in the engine, white smoke may appear. While not ideal, an oil leak is no cause to fail an emissions test.
The analyzer will prompt you if you see smoke. In the case that you do, you will need to input yes on the Analyzer. This will cause the vehicle to fail the test. When explaining a failed test result to a customer, it’s important to note the cause. A smoking crankcase or tailpipe is a common cause, so explain to the customer why the vehicle failed and what they can do about it. As with any cause of failure, it’s important to inform the customer of the possible next steps.
Observing smoke coming from the tailpipe and/or crankcase is only required for the Tailpipe test. It you are performing an OBDII test, then you should only look for smoke from the tailpipe.