The other day I had a 2004 Nissan Sentra 1.8l Auto Trans in for smog. I failed it for timing. The specs call for 18 +/- 5 BTDC. It was showing 10 BTBC with the light and 10 BTDC on the scanner. Customer went to Nissan and they told him yep it's at 10 but we ca... Login to read more.