P0262

P0262 sets when the PCM detects voltage on the cylinder 1 injector low-side driver circuit that stays high when the driver commands the injector ON, indicating an open winding inside the injector, a broken signal wire between the PCM and the injector connector, or a short to battery voltage on the driver circuit. Start with the cheapest tests first: back-probe the injector connector with key-on engine-off and confirm you have battery voltage on the supply side (should read within 0.5V of battery), then measure injector winding resistance pin-to-pin at the injector (typical port-fuel-injection spec 11.4 to 18 ohms at 68F, GDI low-impedance injectors 1.5 to 4 ohms) and compare against the other three cylinders, a delta over 2 ohms on PFI or 0.8 ohms on GDI flags the suspect injector. Scope the driver circuit with key-on and look for the square-wave pulse pulling to near 0V during the ON period, a flat line stuck at 12-14V confirms an open driver path or open winding. The expensive misdiagnosis here is condemning the PCM after a parts-cannon injector swap, the driver transistor inside the PCM can be damaged by a shorted injector but it cannot be tested without isolating the harness first, always unpin the injector connector and recheck before authorizing a PCM replacement.

Vehicle-specific patterns: 2003-2007 Ford 6.0L Powerstroke under-valve-cover harness chafe on the cylinder 1 injector pigtail is the textbook cause, TSB 07-15-2 covers the FICM/UVCH replacement procedure; 2005-2010 Chevy Cobalt/HHR 2.2L Ecotec sees corrosion in the injector connector terminals from coolant weeping past the intake gasket onto the harness; 2007-2013 BMW N54 with HPFP-era piezo injectors throws P0262 when the index code in the DME no longer matches a swapped injector or when the injector itself fails internally, BMW SI B13 01 10 covers the recoding procedure. Estimated repair: $180 to $1,400.