Scottiac

This is purely informational for the next yahoo curious about likely problems when failing a smog check.

First (fail) test:

15mph, 1691 RPM, 15.2 %CO2, 0.1 %O2, 6 PPM HC, 0.00 Meas CO%, 665 Meas NO (PPM)
25mph, 1668 RPM, 15.1 %CO2, 0.1 %O2, 5 PPM HC, 0.10 Meas CO%, 602 Meas NO (PPM)

The fail was the 15mph NO, which had a 512 limit.
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Had the O2 sensor replaced (stealer diagnosed it as bad). New numbers:

15mph, 1692 RPM, 15.1 %CO2, 0.1 %O2, 13 PPM HC, 0.08 Meas CO%, 167 Meas NO (PPM)
25mph, 1680 RPM, 15.1 %CO2, 0.0 %O2, 2 PPM HC, 0.00 Meas CO%, 66 Meas NO (PPM)

Vehicle condition going into the first test: immediately after an oil change (and air filter change), vehicle driven infrequently in the weeks before. Mileage 110k. This was the California smog check, obviously.

As mentioned in several other posts in the past, "vehicle driven infrequently before test" is not the best idea...