it is obviously too late for you but I'll still post this for future reference, and for those who may stumble upon this thread for a similar violation:
Pursuant to VC 40522, an officer arresting for violations specified in Vehicle Code section 40303.5 is required to specify the offense charged and note in a form approved by the Judicial Council that the charge shall be dismissed upon proof of correction.
VC 40303.5. Whenever any person is arrested for any of the following offenses, the arresting officer shall permit the arrested person to execute a notice containing a promise to correct the violation in accordance with the provisions of Section 40610 unless the arresting officer finds that any of the disqualifying conditions specified in subdivision (b) of Section 40610 exist:
(a) Any registration infraction set forth in Division 3 (commencing with Section 4000).
(b) Any driver's license infraction set forth in Division 6 (commencing with Section 12500), and subdivision (a) of Section 12951, relating to possession of driver's license.
(c) Section 21201, relating to bicycle equipment.
(d) Any infraction involving equipment set forth in Division 12 (commencing with Section 24000), Division 13 (commencing with Section 29000), Division 14.8 (commencing with Section 34500), Division 16 (commencing with Section 36000), Division 16.5 (commencing with Section 38000), and Division 16.7 (commencing with Section 39000).
VC 27156(b) is indeed listed under Division 12 (Chapter 5, "Article 2: Exhaust Systems").
Also, VC 40611 authorizes the court to accept the $25 administrative fee if/when proof of correction is submitted and accepted by the court.
There are exceptions (Also Known As "Disqualifying Conditions") to that which are listed under VC 40610(b) where the officer has the discretion to issue this as a "non-correctable" violation... Those conditions are:
1. Evidence of fraud or persistent neglect;I bolded the words that "I" think may have caused the officer to issue this as a "non-correctable" violation.
2. The violation presents an immediate safety hazard;
3. The violator does not agree to, or cannot, promptly correct the violation.
However, and even if the officer issued it as a non-correctable violation, it is still up to the discretion of the court to accept the correction (had you attempted to take that path by bringing your vehicle up to code) and to dismiss the citation accordingly.
My guess is that the judge did not show you any sympathy with regards to your "error" argument due to your apparent defiance and your continuing to operate your vehicle in violation of that particular requirement, rather than make the correction and bring your vehicle up to code.
Point is, you could have tried... But you didn't...
Also keep in mind that if you get pulled over again, and assuming that the officer chooses to look into your driving record, (yes, he can, in fact, see that you have been cited and convicted in violation of 27156(b)), which may lead him to inspect your vehicle and if not corrected, he can issue you another citation for the same violation... And the more citations you get, the easier they can prove that the "persistent neglect" and "your refusal to promptly correct the violation" elements of 40610(b)(1) and (3) do in fact exist...
I realize that none of this is going to convince you to bring your exhaust/emission system up to code, but you should realize that you have opened up a can of worms that may get fairly expensive (at $350 a pop) as time goes by.