P0283

P0283 indicates the cylinder 8 injector control circuit is reading high (open) when it should be pulled low by the driver. Cheapest test: swap injector 8 with a neighboring injector and clear codes. With the connector unplugged, ohm the injector: PFI 11 to 17 ohms, GDI 1.5 to 4 ohms; OL reading confirms a broken winding. Key-on engine-off, back-probe the connector: feed should read battery voltage, driver should rise to within 1V of battery through the injector coil if everything downstream is intact. Scope the driver line at crank and look for a clean ground pulldown under 1.0V at each command; missing pulldown means an open between the PCM and the injector, or a failed driver inside the PCM. Caveat: cylinder 8 is at the back of most longitudinal V8s and the harness routing often passes the firewall bulkhead grommet, so always inspect that grommet area before disassembling further; many shops replace coil packs first by mistake on V8s when both the coil and injector for cylinder 8 share routing.

Vehicle-specific patterns: 2003 to 2008 Dodge Ram 1500/2500 5.7L Hemi has a recurring cracked injector connector body fault on the rear cylinders, fixed with Mopar pigtail kit; 2005 to 2009 Mustang GT 4.6L 3V has rear-bank harness chafe near the firewall heater pipe; 2007 to 2013 Toyota Tundra 5.7L 3UR-FE rarely fails injectors but does have broken connector locking tabs after timing-cover service. Estimated repair: $40 to $510.