P0278 Code: Meaning, Symptoms, Causes & Fix

Overview

Code P0278 indicates a fault in Cylinder 6 Contribution/Balance Fault, typically within powertrain controls.

Symptoms

reduced performance
increased fuel use
check engine light

Common causes

Control module logic or calibration issue affecting cylinder 6 contribution/balance fault
Component failure in the monitored system
Connector pin damage/corrosion or harness stress near related components

How to diagnose P0278

Confirm P0278 and capture freeze-frame data with a professional scan tool.
Inspect wiring, connectors, and grounds related to cylinder 6 contribution/balance fault for obvious defects.
Use freeze-frame and live data to isolate whether the issue is electrical, mechanical, or control logic.
Check for related DTCs to identify the root-cause chain before replacing parts.
After repair, clear codes and confirm readiness monitors complete without recurrence.

Severity of code P0278

Low: This code is low to moderate severity in most cases, but diagnosis is still recommended to avoid recurring warnings.

Can you drive with P0278?

The vehicle is often drivable with P0278, but plan a repair window to prevent repeat faults.

If the warning lamp is flashing or drivability/safety is affected, avoid driving and diagnose immediately.

How to fix it (step-by-step)

Repair obvious wiring/connector faults first to prevent repeat parts replacement.
Address the root fault mode (generic) in the cylinder 6 contribution/balance fault circuit/system.
Apply the required relearn/adaptation procedure if specified by service information.
Road-test and verify P0278 remains cleared under the conditions that originally set the code.

Fix options

Clear code and confirm through drive cycle.
Inspect circuit and connector condition.
Clear DTCs and verify with live data and completed drive cycle.

Typical repair cost

$100-$450

Common mistakes when diagnosing P0278

Replacing parts without verifying voltage, ground, and signal integrity first.
Ignoring related stored/pending codes that indicate upstream faults.
Skipping post-repair verification drive cycle and readiness checks.

P0278 in common vehicles

P0278 appears across makes such as Ford, Toyota, Honda, Chevrolet. Failure patterns differ by platform: wiring routes, software calibration, and component supplier revisions can change root cause.

Frequently asked questions

What causes P0278?

P0278 is commonly set by generic faults affecting cylinder 6 contribution/balance fault.

How much does it cost to fix P0278?

For P0278, repair costs are typically $100-$450 depending on exact root cause, labor rates, and part quality.

Can I clear P0278 without repair?

You can clear P0278 temporarily, but the code usually returns until the underlying fault is corrected.