P0277: Cylinder 6 fuel injector circuit reads high voltage
Injector 6 circuit high / cylinder 6 injector circuit high
Severity: Severity not verified — if the car runs badly, have it inspected
No source here rates the urgency of an injector circuit fault, so the class is not verified. One cylinder may get the wrong fuel delivery, so the engine can run rough or lose power.
It gets more serious if:
- Inspect soon: Inspect soon if the engine runs rough, loses power or knocks. TroubleCodes.net lists these as symptoms of an injector circuit problem.
P0277 in short
P0277 means the engine computer found the cylinder 6 fuel injector circuit reading high voltage. Wiring faults, a loose or corroded connector, or a faulty injector are the usual causes. Rough running or power loss means have it checked soon; a steady light alone can wait a short while.
The computer drives each fuel injector through its own circuit and watches the voltage on it. P0277 is the code for cylinder 6: the circuit voltage was high when the computer checked it.
TroubleCodes.net lists wiring that is shorted to ground, loose or corroded connectors and a faulty injector control module for the low-voltage version, and a short to positive, the injector or the computer for the high-voltage version. The computer itself is the least likely cause.
Because the code names one cylinder, the check starts at that injector and its connector.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Short, open or loose or corroded connector in the injector circuit
Common general cause- Why it ranks here
- TroubleCodes.net names wiring shorts and connector problems among the main causes: Wiring short to positive, a faulty injector or engine computer.
- What would change this
- Rises if the connector is loose, green or wet or the harness is damaged. Falls if the wiring tests good.
Cause 2: Faulty injector on cylinder 6
Common general cause- Why it ranks here
- The injector is listed as a possible cause on the reference page; check it once the wiring is cleared.
- What would change this
- Rises if the injector does not click or its coil reading is out of range. Falls if it clicks and tests like the others.
Cause 3: Injector driver or control module, or the engine computer
Possible — needs testing- Why it ranks here
- Listed as a less common cause; check only after the injector and wiring pass.
- What would change this
- Rises if power reaches the injector but the driver does not switch it. Falls if the circuit or injector is at fault.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: With the engine off, look at the cylinder 6 injector connector and wiring for looseness, corrosion or damage.
IfDamage or corrosion is found
It meansRepair the wiring or connector first.
Points to: Short, open or loose or corroded connector in the injector circuit
IfThe wiring looks sound
It meansCheck whether the injector operates.
Step 2: Have the injector listened to with the engine running, and compare it with the others.
Warning:The engine is running with belts and fans next to the injectors. A shop should do this.
IfNo click or a weak click
It meansThe injector is not operating.
IfA normal click
It meansLook for an intermittent wiring fault.
Points to: Short, open or loose or corroded connector in the injector circuit
Step 3: Check for power at the injector connector and whether the engine computer switches the other side.
Warning:Injector circuits can carry high voltage on some engines; back-probe with the right meter or leave it to a shop.
IfPower and switching are present but the injector does not work
It meansThe injector is faulty.
IfPower or switching is missing
It meansWiring, driver or computer.
Points to: Injector driver or control module, or the engine computer
Symptoms
- Check engine light
- Rough running
- Loss of power during acceleration Gets more serious: stop and have it checked.
Compare with: Car shaking with the check engine light on
How to fix
Step 1: With the engine off and cool, check that the injector connector for that cylinder is fully seated and free of corrosion.
Parts and cost context
- Fuel injector:Test the injector and wiring before replacing; labor varies, get a quote.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
We don't have reviewed vehicle-specific evidence for P0277 yet. The causes and tests above apply across vehicles.
Related codes
No curated relationships for P0277 yet.
Sources and review
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error