The P0279 code on your 2020 Ford Mustang indicates a low voltage condition in the cylinder 7 fuel injector circuit. This code applies to V8-powered Mustangs, pointing to a specific cylinder for focused diagnosis.
Mustang V8 Engine Options
The 2020 Mustang offers the 5.0L Coyote V8 (GT) and the supercharged 5.2L V8 (Shelby GT500). The EcoBoost 2.3L four-cylinder wouldn't have a cylinder 7. On Ford's Coyote V8, cylinders are numbered 1-2-3-4 on the passenger bank and 5-6-7-8 on the driver bank.
Low Circuit Causes
A low reading indicates a short to ground in the cylinder 7 circuit. The injector coil may have internal shorts, wiring may contact the block or exhaust, or connector corrosion creates ground paths. The performance engine environment generates heat that can accelerate wire insulation breakdown.
Diagnostic Approach
Locate cylinder 7 on the driver's side bank, third from the front. Disconnect the injector and measure coil resistance—Coyote injectors should read approximately 12-15 ohms. Test for continuity between the circuit wires and ground. Inspect wiring routing near exhaust headers and the engine block for chafing.
Repair Path
Shorted injectors require replacement. Coyote injectors are high-flow units designed for the performance engine. For wiring shorts, repair with proper techniques and add heat protection. After repair, clear codes and enjoy your V8's full eight-cylinder symphony.