Question 1

How is diesel smog different from gasoline?

Accepted Answer

Diesel checks use no tailpipe sniffer. OBD scan only. Visual emissions component inspection. Smoke opacity test for some. Per BAR diesel inspection requirements.

Question 2

Do diesel trucks need smog check in California?

Accepted Answer

Yes — diesel trucks from the 1998 model year and newer need a smog check. Under 14000 lbs gvwr. Biennial inspection required. Heavy-duty falls under clean truck check. Per BAR diesel inspection requirements.

Question 3

Will a DPF delete fail my diesel smog?

Accepted Answer

Yes — the visual inspection catches it. DPF removal is illegal in California. Must restore stock DPF to pass. BAR can impose fines. Per BAR diesel inspection requirements.

How is diesel smog different from gasoline?

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