Error code

OBD2 P0278

OBD2P0278
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Cylinder 6 Contribution/Balance.

Severity

moderateCan drive but may experience reduced performance and fuel efficiency.

Summary

P0278 indicates that cylinder #6 is not contributing properly to engine balance and efficiency. This issue can be detected by the Engine Control Module (ECM) through monitoring crankshaft position.

Symptoms

  • Reduced engine performance
  • Poor fuel economy
  • Rough idle

Common Causes

  • Dirty or clogged fuel injectors
  • Improper replacement of fuel injectors without proper learning procedure
  • Mechanical issues such as worn rings, burnt valves, or leaking head gasket

Diagnosis

  1. Check for corrosion or water damage in the fuel injector connectors
  2. Compare waveforms of cylinder #6 fuel injector with neighboring injectors using a digital oscilloscope
  3. Perform cylinder compression and leakdown tests to identify mechanical issues

Fixes

  • Clean or replace the fuel injectors

FAQ

What does P0278 mean?

P0278 indicates that cylinder #6 is not contributing properly to engine balance and efficiency.

How do I fix P0278?

Cleaning or replacing the fuel injectors, performing a proper learning procedure for new injectors, and addressing mechanical issues like worn rings or valves can resolve this code.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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