OBD codes / P0280
P0280
ModerateCylinder 7 Injector Circuit High
Even if the engine still feels strong, an erratic cylinder 7 sends unburned fuel into that bank's catalytic converter. Continued driving risks converter overheating, so schedule the repair soon and treat a flashing check-engine light as a stop-driving event.
What this code means
P0280 is the high-voltage counterpart to P0279: the ECM caught the cylinder 7 injector circuit reading above its expected range. That usually means the circuit is touching battery voltage through damaged insulation, or that resistance has crept in through a corroded connector, a failing terminal, or an injector winding that has gone open. Since this monitor tracks electrical behavior rather than fuel flow, it's a different problem from a clogged injector — no additive will help. You'll only see this code on engines with seven or more cylinders, primarily V8s and up, and the abundance of identical sibling circuits makes comparison testing easy. Watch for P0207 (circuit) and P0307 (misfire) stored with it. Because manufacturers number V-engine banks differently, verify cylinder 7's physical location on your engine before pulling connectors.
Symptoms you might notice
- Cylinder 7 misfire — may feel like a light stumble on a V8
- Slightly rough idle and reduced smoothness
- Power loss under load or towing
- Check-engine light; flashing signals an active misfire
- Possible code storage with no symptoms if intermittent
What it costs to fix
Typical range: $60–$450 · about ~0.5–2 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Fuel injector (single) | $50–$300 | ~0.5–2 hrs |
| Wiring/connector repair | $5–$50 | ~0.5–2 hrs |
Connector and wiring repairs are inexpensive; the injector is the bigger cost. On V-engines the intake often has to come off to reach the injectors, and direct-injection injectors are pricier parts — both push toward the top of the range.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0280 for my exact vehicle →
Frequently asked
How is P0280 different from P0279?
They monitor the same cylinder 7 injector circuit in opposite directions. P0279 fires on low voltage (short to ground, shorted coil); P0280 fires on high voltage (open circuit, corrosion resistance, or a short to battery voltage). The direction tells the technician which failure modes to hunt.
Can corrosion really set this code?
Absolutely — it's one of the most frequent causes. Oxidized connector pins add resistance that distorts the voltage the ECM sees when it fires the injector. A visual inspection and cleaning of the cylinder 7 connector is a free first step that solves a surprising number of these.
Do I have to stop driving right away?
Not usually. With a steady light and mild symptoms, careful short-distance driving is acceptable while you arrange the repair. The exceptions are a flashing check-engine light or a strong misfire — both mean the catalytic converter is at active risk and the car should be parked.
Why would this code appear and disappear?
Marginal connections behave that way: a corroded pin or nicked wire conducts normally until heat, moisture, or vibration breaks the contact, sets the code, then reconnects. Intermittent behavior is a strong clue to focus on the connector and harness rather than the injector body.
Seeing P0280 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0280 for my vehicleRelated trouble codes
Don’t have a scanner yet? A ~$25 Bluetooth adapter reads codes like P0280 from your phone — see our honest guide to the best OBD2 Bluetooth adapters.
Generic OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.