P0280
Cylinder 7 Injector A Circuit High.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 2
- AreaFuel and air metering (injector circuit)
- 80
- FaultThe specific fault in that area
What it means
P0280 means the engine control unit has detected a high voltage or high signal condition on the injector circuit for cylinder 7 (injector A on systems with more than one injector per cylinder). The control unit monitors the injector driver circuit and found a reading outside the expected range, such as a short to voltage, an open circuit or a driver fault. Cylinder 7 only exists on engines with seven or more cylinders, so the cylinder numbering and injector location depend on the engine.
Symptoms
- Engine warning light on
- Misfire or rough running, mainly on one cylinder
- Noticeable loss of power or poor acceleration
- Hard starting or extended cranking
- Poor fuel economy or a fuel smell from the exhaust
- Engine may run in a reduced-power or limp mode
Possible causes
- Damaged, chafed or corroded wiring between the injector and the control unit, causing a short to voltage or an open circuitlikely
- Poor connection at the cylinder 7 injector plug or the control unit connector (corrosion, bent or loose pins, water ingress)likely
- Faulty cylinder 7 injector with an internal electrical fault (open or shorted coil)likely
- Fault in the injector driver circuit inside the engine control unitpossible
- Wiring harness damage from heat, vibration or earlier engine repair workpossible
- Power supply or earth fault affecting the injector circuit on that bankpossible
- Outdated or faulty control unit software, only where the manufacturer has published it as a known cause for this enginerare
How to diagnose
- Read all stored and pending codes and the freeze frame data, noting engine load, temperature and speed when the fault set; look for related misfire codes on cylinder 7.
- Confirm which physical injector is cylinder 7 for this engine, as the numbering and layout vary by model and engine.
- Visually inspect the cylinder 7 injector, its connector and the surrounding harness for chafing, heat damage, corrosion, oil contamination or loose pins.
- Wiggle-test the harness and connector with the engine running or the live data displayed, watching for the fault or a misfire appearing.
- Measure the injector coil resistance and compare it with the manufacturer specification for that engine.
- Check the injector supply voltage and earth at the connector with the circuit live, following the wiring diagram.
- Use a scan tool's active test or an oscilloscope to check the injector drive signal from the control unit for cylinder 7.
- Check the wiring continuity and for shorts to voltage between the injector and the control unit, with the connectors disconnected; only suspect the control unit once the wiring and injector are proven good.
How to fix
- Repair or replace damaged wiring and fix any short to voltage or open circuit found.
- Clean, repair or replace a corroded or damaged injector or control unit connector.
- Replace the cylinder 7 injector if its electrical values are out of specification, and follow any coding or adaptation steps the manufacturer requires.
- Repair the supply or earth fault affecting the injector circuit.
- Repair or replace the engine control unit if the driver circuit is confirmed faulty, with the required programming.
- Apply a manufacturer-released software update only where it is a documented fix for this fault.
Can I keep driving?
The car can usually be driven a short distance to a workshop, but have it checked soon. A misfiring or constantly open injector can cause rough running, fuel dilution of the oil, catalytic converter damage or engine damage, so avoid heavy loads and stop if it runs badly or flashes the warning light.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.