Fuel and air

P0277 — Cylinder 6 Injector Circuit High

Severity: medium Drive with care, to a shop

What P0277 means

The engine control unit fires the cylinder 6 injector through a driver circuit and monitors the voltage and current in that circuit. P0277 sets when the signal goes above the allowed range. Common causes are a short to voltage, a failed injector coil, or a poor connection at a connector. Less often, the injector driver inside the control unit has failed.

Symptoms

  • Check Engine light on
  • Rough idle
  • Misfire, often on cylinder 6
  • Reduced power and sluggish acceleration
  • Worse fuel economy
  • Fuel smell from the exhaust if the injector leaks or sticks

Possible causes

  1. Damaged or shorted wiring in the cylinder 6 injector circuit
  2. Failed cylinder 6 injector (internal short or open coil)
  3. Injector circuit shorted to battery voltage
  4. Corroded or loose connector at the injector or the PCM
  5. Failed injector driver inside the PCM

How to diagnose

  1. Scan all codes and freeze-frame data and look for other injector codes
  2. Inspect the injector 6 connector and harness for chafing, heat damage, corrosion and tension
  3. Measure injector coil resistance and compare it with neighboring injectors and factory specs
  4. Test the circuit for a short to voltage or ground, and check continuity to the PCM
  5. Check the injector control signal with a scope or noid light
  6. Swap the injector with a neighbor and see whether the problem follows it
  7. Inspect the PCM connector pins and the injector power supply
  8. Review fuel trims, cylinder balance and fuel pressure

Common fixes

  • Repair or replace the damaged injector wiring or connector
  • Replace the faulty cylinder 6 injector
  • Clean the contacts or replace corroded terminals
  • Repair or replace the PCM if the injector driver is bad
  • Clear the code and confirm it does not return

Questions and answers

What does P0277 mean?

It means the control unit sees a too-high signal in the cylinder 6 injector circuit. The usual causes are wiring, the injector itself or a poor connection.

Can I drive with P0277?

Only briefly and carefully, to a shop. The engine may misfire and lose power, and excess fuel can harm the catalytic converter and the oil.

Should I replace the injector right away?

No. Check the wiring, connector and injector resistance first, and replace the injector only if it tests bad.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.