P0286

P0286 indicates the cylinder 9 injector driver is reading high, meaning open circuit on the driver-side wire, broken winding, or a disconnected/corroded connector. Cheapest test: swap injector 9 with a neighbor; if the code follows the injector, the winding is open. Ohm test: PFI 11 to 17 ohms (Ford 6.8L Triton, Viper 8.3L), GDI-style 1.5 to 4 ohms (BMW S85). Key-on engine-off, the feed pin should read battery voltage; the driver pin should rise to within 1V of battery through the coil when injector is connected. With injector disconnected and key on, driver pin should read 0V if PCM driver is healthy. Caveat: on the Ford 6.8L 2V Triton, the cylinder 9 injector connector is buried under the upper intake plenum on most chassis configurations and the wire harness must be inspected from the connector all the way back to the firewall pass-through; spark plug blowouts on cylinder 9 are common and can sever the injector harness.

Vehicle-specific patterns: 1999 to 2010 Ford E-350/E-450 and F-Super Duty 6.8L V10 Triton sees P0286 most often from harness damage after a cylinder 9 spark plug blowout, repaired by helicoil or Time-Sert plus harness repair; 2006 to 2010 BMW M5/M6 S85 V10 has weak injector solder joints inside the connector body; 2003 to 2010 Dodge Viper 8.3L V10 SRT-10 has cracked Bosch injector connectors from underhood heat cycling. Estimated repair: $60 to $1,100.