P013F fires when the downstream O2 sensor (Bank 1, Sensor 2) is too slow to transition rich-to-lean during a catalyst-monitor test...

P0884 fires when the TCM detects intermittent drops or interruptions on its battery supply — causing false neutral events, harsh shifts,...

P0914 fires when the gear shift position sensor circuit reports an electrical fault — no-start in park, random gear lockout, or...

P0556 fires when the brake booster pressure (vacuum) sensor reads outside its calibration window — risking hard brake pedal, increased stopping...