Injector wiring for cylinder 6 shorted to a voltage supply or chafed against other wiring; Faulty cylinder 6 fuel injector with an internal electrical fault; Damaged, corroded or loose connector at the injector or control unit; Poor earth or power supply affecting the injector circuit; Fault in the injector driver inside the engine control unit; Water ingress or heat damage in the harness near cylinder 6.

P0277

Cylinder 6 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)
77: FaultThe specific fault in that area

What it means

P0277 is a generic powertrain code meaning the engine control unit has detected a high signal or voltage fault in the injector circuit for cylinder 6. The control unit monitors the injector driver circuit and sets the code when the voltage or current is higher than expected, which can point to a short to voltage or a fault in the driver. The exact injector circuit layout and the meaning of 'A' depend on the engine and fuel system.

Symptoms

Engine warning light on
Misfire or rough running, especially on cylinder 6
Poor acceleration or hesitation
Rough idle or uneven idle
Increased fuel consumption
Engine may go into limp mode or run on fewer cylinders

Possible causes

Injector wiring for cylinder 6 shorted to a voltage supply or chafed against other wiringlikely
Faulty cylinder 6 fuel injector with an internal electrical faultlikely
Damaged, corroded or loose connector at the injector or control unitpossible
Poor earth or power supply affecting the injector circuitpossible
Fault in the injector driver inside the engine control unitrare
Water ingress or heat damage in the harness near cylinder 6rare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including engine load, speed and temperature when the fault set
Check for other injector or misfire codes, as these help to separate a cylinder 6 fault from a wider circuit problem
Visually inspect the cylinder 6 injector connector and the harness for chafing, heat damage, corrosion and bent or pushed-back pins
Check the injector coil resistance against the manufacturer's specification for your engine
Check the injector wiring for a short to voltage or a short to earth, and for continuity back to the control unit, with the connectors disconnected
Check the injector supply voltage and the relevant fuses and relays using the wiring diagram for your model
Swap the cylinder 6 injector with another cylinder where practical and see whether the fault follows the injector
If wiring and injector test fine, check the control unit power and earths before considering the control unit itself

How to fix

Repair or replace the damaged section of wiring and secure it clear of heat and sharp edges
Replace the cylinder 6 injector if it fails electrical tests, and follow any coding or adaptation steps the manufacturer requires
Clean, repair or replace the faulty connector or terminals
Restore good power and earth connections to the injector circuit
Repair or replace the engine control unit only after all wiring and injector faults have been ruled out and the driver fault has been confirmed
Clear the codes after the repair and road test to confirm the fault does not return

Can I keep driving?

Medium severity

The car may be driven a short distance if it runs acceptably, but get it checked soon. A faulty injector circuit can cause misfires that may damage the catalytic converter, so avoid hard driving and stop if it runs badly or goes into limp mode.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.