OBD-II trouble code
P0276: Cylinder 6 Injector Circuit Low
The cylinder 6 injector control circuit read low — usually a wire shorted to ground or a shorted injector coil. On most V6 and V8 engines cylinder 6 sits at the back, where access drives the labor cost more than the part does.
Quick facts
- System
- Powertrain
- Category
- Fuel Injectors
- Severity
- Medium severity
- Drivable
- No — stop driving until repaired
- Repair cost range
- $50 – $1,500
- DIY difficulty
- Intermediate DIY
What does P0276 mean?
The engine control module (ECM) switches each fuel injector on the ground side. Switched battery voltage sits on one injector terminal, and the ECM fires the injector by pulling the other terminal to ground for a metered pulse width. Between pulses that control wire should read close to battery voltage, since nothing should be tying it to ground.
P0276 sets when the ECM sees the cylinder 6 control circuit reading low while it expects high — the circuit is grounded when it should be floating. The usual causes are a control wire that has chafed through and contacted the block, head, or a bracket, an injector with a shorted coil winding, or corrosion and moisture bridging pins inside the connector. Some platforms also set the code when measured current through the circuit falls below the expected range.
What makes cylinder 6 different from cylinders 1 through 4 is not the electrical theory — it is access. On a transverse V6 in a front-wheel-drive car, cylinder 6 is typically on the rear bank, wedged against the firewall under the intake manifold, and reaching its injector connector can mean removing the upper intake plenum, the throttle body, and a cover or two. On a longitudinal V8, cylinder 6 sits well back on one bank near the cowl. In both cases the injector itself may cost under $150, while the labor to reach it can be several times that. This changes the diagnostic calculus: it is worth being certain about which component is at fault before disassembly begins, because a wrong guess costs the whole teardown twice.
It also changes the odds on which cause is likeliest. Rear-bank and rearward-cylinder harnesses live in the hottest, least ventilated part of the engine bay, and they collect moisture and debris that wash down from the cowl. Chafe, heat-hardened insulation, and green corrosion inside the connector are all more common there than at the front of the engine — which means a careful physical inspection of the connector and harness routing is worth doing before you condemn the injector.
With the circuit low, cylinder 6 is not being fueled the way the ECM intends, so a misfire is likely and P0306 often appears alongside. Unburned fuel entering the exhaust can superheat the catalytic converter on that bank, so the code should not be left to sit.
Common causes
- Cylinder 6 injector control wire chafed through and shorted to ground
- Shorted coil winding inside the cylinder 6 injector
- Corrosion or water intrusion in the injector connector, common on rear-bank cylinders that collect cowl runoff
- Heat-hardened or melted harness insulation near the exhaust manifold or turbocharger on that bank
- Wire pinched or trapped during a prior intake manifold or valve cover repair
- Damaged, spread, or backed-out terminal in the injector connector
- Rodent damage to the injector harness where it runs along the back of the engine
- Rarely, a failed cylinder 6 injector driver circuit inside the ECM/PCM
Symptoms
- Check engine light on, sometimes flashing under load
- Rough idle with a noticeable engine shake
- Misfire on cylinder 6, commonly with a companion P0306
- Loss of power and hesitation under acceleration
- Raw fuel smell from the exhaust
- Increased fuel consumption
- Hard starting or extended cranking in some cases
Diagnostic steps
- 1.Confirm P0276 and record all companion codes. A cylinder 6 misfire (P0306), the paired high code P0277, or a balance fault (P0278) each shift the emphasis.
- 2.Identify cylinder 6 for your exact engine in the service information. On most transverse V6s it is on the rear bank; on longitudinal V8s the bank assignment depends on the manufacturer.
- 3.Before any disassembly, test as much as possible from the accessible end. Check for continuity to ground on the cylinder 6 control wire at the ECM connector with the ECM unplugged — a short in the harness can often be confirmed without touching the intake manifold.
- 4.Inspect whatever portion of the harness you can see for chafe, heat damage, and green corrosion at the connector. Rear-bank harnesses fail this inspection more often than front-bank ones.
- 5.Once you have access, unplug the injector with the key off and measure its coil resistance. A reading well below specification and well below the other injectors confirms a shorted coil.
- 6.With both the injector and the ECM disconnected, recheck the control wire for continuity to ground. Continuity confirms a harness short rather than a bad injector.
- 7.Wiggle-test the harness along the back of the engine, focusing on manifold studs, bracket edges, and any point where the loom has worn through.
- 8.With the wiring and injector verified good, use a noid light or the scan tool injector test to confirm the ECM is pulsing the circuit normally.
- 9.If everything external tests correct, suspect the ECM injector driver — verify with the manufacturer's pinout procedure before condemning the module.
Repair cost
$50 – $1,500
Repairing a chafed wire or a corroded connector is often $75-$250 when the wire is reachable, and considerably more when the intake manifold has to come off to get to it. A single fuel injector is $60-$400 in parts, but labor is the deciding factor on cylinder 6: an accessible port injector is 0.5 hours while a rear-bank injector under a V6 plenum commonly runs 2-3 hours, and shops often quote intake gaskets at the same time. Diesel injectors on an inline six typically land at $400-$900 installed. A failed ECM injector driver is uncommon and runs $500-$1,500 including programming. Diagnosis alone is typically $75-$150.
Estimate your repair
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Open the Repair Cost Estimator with fuel injector replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.