If your car is MY 2010 or newer, need a smog test, and have Permanent Diagnostic trouble codes present, you will fail smog.
Smog Check Station operators across the state of California started getting notices that starting July 2019, cars coming in for the simpler BAR-OIS or On-Board Diagnostic Inspection, as well as not having any Diagnostic Trouble Codes and Readiness Monitors not completed, you must also not have any Permanent Diagnostic Trouble Codes, not to be confused with the aforementioned DTC’s you can clear with a scan tool.
This latest initiative was put into place as the Bureau of Automotive Repairs has caught on to people unplugging their battery or clearing codes prior to getting a smog check. Although readiness monitors can still be set even after clearing DTC’s, Permanent DTC’s still remain. Even having one PDTC present means an automatic fail.
According to Smog Technicians on this Smog Forum,
Permanent fault codes are stored in NVRAM (Non-Volatile Random Access Memory), which means they survive clearing with a scan tool (Mode $03), or loss of KAM from battery disconnect. Permanent fault codes can only be erased by the Diagnostic Exectutive (Chrysler calls him the Task Manager) in the PCM.
If you don’t have a check engine light on and haven’t had it on for a while in your MY 2010 or newer vehicle, it’s safe to assume you won’t have any PDTC’s when you DO get a smog test.
But, if you’ve recently cleared all DTCs with a scan tool or battery reset, your car probably has a PDTC. The only way to get rid of that PDTC is to address the underlying issue that caused it. Then, you must run either a Universal Drive Cycle or a specific drive cycle that pertains to your PDTC.
There are specific drive cycles you can find for your particular car. Nissan, for example, has a pretty specific drive cycle that should clear any PDTC’s in less than half an hour.
BAR cites, as a rule of thumb, about 15 start/stop cycles and 200 miles of driving as the upper limit for a PDTC to clear.
BAR expects failure rates of cars to increase by between .2-.3 percent although we’ll wait and see when this new part of the smog check starts.
If you’re a smart consumer like myself and own a MY 2010 car or newer and want to be doubly sure when you do buy your own OBD2 scanner to check on PDTC status, be sure your OBD2 scanner can even read PDTCs as I presume the cheaper ones can’t.
Do you have anything constructive to add to the discussion? Let me know your thoughts in the comments below.
Source: BAR
