Subaru Impreza 2014 — technical service bulletin
Bulletin 11-186-18 · NHTSA communication 10153610 · issued Dec 3, 2018
Technical service bulletin
communication type
Electrical System
component
2014
model years
1
vehicle entries
Official summary
This bulletin announces availability of reprogramming files to optimize the ECM. These files enhance detection of DTC P0300: RANDOM/MULTIPLE CYLINDER MISFIRE DETECTED. If a customer presents with a rough idle concern and / or hesitation after a cold start when using winter-blend fuels, reprogram the ECM following the normal FlashWrite procedure. The new logic contains revised A/F, ignition timing and alternator controls designed to prevent an over-lean fuel mixture condition at cold start and stabilize the engine idle.
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.