2001 Chevrolet Impala Q&A
2001 Chevrolet Impala Question: My emission test failed due to problem control system vent control circuit malf.
You may have a blown fuse if the test equipment not communicating with your computer. I don't understand how they pulled code regarding control vent system vent control malfunction unless maybe was still pending on computer. This problem originally with your purge valve or fuel pressure sensor for evap emissions. The Mil command just note that an original trouble code was set but if problem was corrected drive cycles since then should have fixed that even if they didn't reset computer. With this stuff service engine light should have been on alerting you to have checked before test. - rpclements