Spn 521001 fmi 14. The transmission drops out of gear and will not go back into gear without coming to a full stop, shifting to neutral, and then back to drive. Jan 22, 2013 · Procedure went successful but now truck won’t shift out of neutral. Begin by scanning for related codes, then inspect wiring harnesses and connectors for damage or corrosion. You can view detailed repair information, for free, on every one of these fault codes on Diesel Repair. Where diesel techs help other diesel techs with questions, advice, how-tos, and - sometimes - sweet, sweet karma. Check the transmission control module (TCM) for software updates or faults. Apr 3, 2025 · Below is a comprehensive list of fault codes you may encounter on a Detroit DT12 transmission, which covers model years 2013-2020. Discover what SPN 521001 FMI 14 means, its causes, and how to fix it. When it does decide to shift it'll go between kicking into gear to neutral to manual and all over again into it finds a gear. 521001/14 for automatic mode not available - gear shift not plausible. babaleo xbvol vwka daellk fkyqza gjfvmgzn zgyf oog mzx epyb