P0280
Cylinder 7 Injector Circuit HighP0280 is a generic OBD-II powertrain diagnostic trouble code: Cylinder 7 Injector Circuit High. It is logged by the engine control unit when the fuel/inj monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0280 means
P0280 is set when the engine control module (ECM) detects that the voltage or current on the fuel injector control circuit for cylinder 7 is higher than the expected specification for more than a calibrated period of time. This fault is exclusive to engines with at least seven cylinders — V8, V10, V12, and inline-8 configurations — and will not appear on four- or six-cylinder engines.
The injector circuit operates by grounding the injector solenoid through an internal ECM driver transistor; abnormally high circuit voltage typically indicates a short to power in the wiring harness, an internal coil fault within the injector itself, or degradation of the ECM's driver transistor or voltage regulator. Corroded or loose connector pins at the cylinder 7 injector can also increase circuit resistance to the point where the ECM registers an out-of-range high reading.
Left unaddressed, a cylinder 7 injector circuit fault can cause persistent misfires that damage the catalytic converter, foul the spark plug, and degrade the upstream oxygen sensor. Prompt diagnosis and repair are warranted to prevent escalating repair costs and further drivetrain damage.
Common causes
Most-frequently reported root causes when P0280 is logged.
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1
Short to power (B+) in the wiring harness between the ECM and the cylinder 7 injector connector.
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2
Corroded, bent, or loose pins at the cylinder 7 injector electrical connector increasing circuit resistance.
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3
Failed or internally shorted fuel injector solenoid coil on cylinder 7.
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4
Degraded or failed ECM internal driver transistor for the cylinder 7 injector output.
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5
Chafed or damaged injector wiring harness contacting a ground or power source.
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6
Faulty ECM voltage regulator causing elevated output on the injector driver circuit.
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7
Software calibration error in the ECM causing misinterpretation of a normal signal as high voltage.
Symptoms drivers notice
How to diagnose P0280
A typical diagnostic flow when this code is present.
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1
Connect an OBD-II scanner, record all stored DTCs, and note freeze-frame data to identify operating conditions at fault set.
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2
Visually inspect the cylinder 7 injector connector and wiring harness for corrosion, chafing, melted insulation, or loose pins; repair any defects found.
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3
Measure injector solenoid resistance with a digital multimeter (typical spec: 12–18 Ω for port injectors, 0.5–2 Ω for GDI injectors); replace the injector if out of specification.
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4
Perform a voltage drop test on the injector control circuit with the engine cranking to check for a short to power; compare to manufacturer wiring diagrams.
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5
Swap the cylinder 7 injector with a known-good injector from another cylinder and recheck — if the fault follows the injector, replace it.
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6
Check ECM driver output voltage during commanded injection using a lab scope; a waveform above the specified high-side voltage confirms an internal ECM driver fault.
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7
Clear codes after all repairs, perform a road test under the freeze-frame conditions, and confirm no recurrence before returning the vehicle.
Related powertrain codes
- P0065 — Air Assisted Injector Control Range/Performance
- P0066 — Air Assisted Injector Control Circuit or Circuit Low
- P0067 — Air Assisted Injector Control Circuit High
- P0087 — Fuel Rail/System Pressure - Too Low
- P0088 — Fuel Rail/System Pressure - Too High
- P0089 — Fuel Pressure Regulator 1 Performance
Frequently asked questions
Which engine configurations can trigger P0280?
P0280 can only appear on engines with seven or more cylinders — V8, V10, V12, and inline-8 (I8) layouts. Four-cylinder and six-cylinder engines do not have a cylinder 7, so this code will never be set on them.
Can I drive with P0280 active?
Short distances at reduced load may be possible, but continued driving risks catalytic converter damage from unburned fuel, spark plug fouling, and oxygen sensor degradation. Diagnosis and repair should not be delayed.
How does P0280 differ from P0261 (Cylinder 1 Injector Circuit Low)?
P0261 indicates a low-voltage (open circuit or short to ground) condition on cylinder 1's injector, while P0280 indicates a high-voltage condition on cylinder 7's injector. Both affect injector operation but point to opposite electrical fault types and different cylinders.
Is the ECM always the cause when the wiring and injector test good?
Not always — a software calibration error or a corrupted driver table can produce a false high-voltage flag. Verify whether a manufacturer-issued calibration update is available before condemning and replacing the ECM.
Disabling P0280 in software
RaceTune can permanently disable P0280 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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