P0268

P0268 is the cylinder 3 variant of the injector-circuit-high family, the PCM expected to pull the driver line low during the commanded injection event and instead saw the line remain at or near battery voltage, which means current is not flowing through the injector winding to ground through the PCM. The three viable root causes are an open injector coil, an open or broken driver wire between PCM and injector, or a short to power that masks the driver pulldown. Start at the injector connector: measure winding resistance at room temperature (PFI 11.4-18 ohms, GDI 1.5-4 ohms, diesel solenoid 0.3-1.5 ohms), compare against the other cylinders, anything off by more than 15 percent is suspect. Confirm 12V on the feed side key-on, then jumper a noid light or known-good injector across the harness pins and crank, no flash means the driver circuit or PCM is the fault, a healthy flash exonerates the harness and points to the injector. Caveat on expensive misdiagnosis: on V6 and V8 platforms cylinder 3 often lives under an intake manifold or valve cover that has to come off for access, do not authorize a $400-600 manifold-off injector R&R until you have actually ohmed the injector through the harness and isolated the fault to the injector itself, a wiring fault upstream means you tear the engine down for nothing.

Vehicle-specific patterns: 2001-2004 Toyota Tacoma/4Runner 3.4L (5VZ-FE) has a known cylinder 3 injector harness rub against the upper intake plenum bracket, the chafe shorts the driver to plenum ground intermittently; 2011-2014 Ford F-150 3.5L EcoBoost first-gen sees cylinder 3 injector failures from carbon-soaked tips loading the winding, TSB 14-0194 covers the cleaning procedure and updated injector part number; 2005-2009 Subaru Legacy/Outback 2.5L EJ253 throws P0268 when the under-manifold injector sub-harness connector fills with oil from a leaking valve cover gasket and shorts internally. Estimated repair: $220 to $1,100.