Fuel and air

P0274 — Cylinder 5 Injector Circuit High

Severity: medium Drive with care, to a shop

What P0274 means

The engine control module fires the cylinder 5 injector by switching its circuit to ground through an internal driver. P0274 sets when the signal in that circuit reads higher than expected. Typical reasons are a short to voltage, a failed injector coil, or a faulty driver inside the module.

Symptoms

  • Check Engine light on
  • Rough idle and engine vibration
  • Cylinder 5 misfire
  • Loss of power and sluggish acceleration
  • Worse fuel economy
  • Higher exhaust emissions

Possible causes

  1. Failed cylinder 5 fuel injector (open or shorted coil)
  2. Damaged, corroded or chafed wiring or connector at injector 5
  3. Control wire shorted to battery voltage
  4. Poor ground or unstable voltage supply to the injectors
  5. Faulty injector driver inside the ECM/PCM

How to diagnose

  1. Scan for codes and freeze frame data, and note any other injector or misfire codes
  2. Inspect the injector 5 connector and harness for corrosion, chafing, heat damage or moisture
  3. Measure injector resistance and compare it with the spec and with neighboring injectors
  4. Check for supply voltage at the injector connector with the ignition on
  5. Test the control wire for a short to voltage and for continuity to the ECM
  6. Swap injector 5 with a neighbor and see whether the code or misfire follows
  7. Review cylinder balance and fuel trims, and check fuel pressure
  8. If the wiring and injector are good, test the ECM driver

Common fixes

  • Repair damaged wiring and replace corroded connectors
  • Replace the cylinder 5 injector
  • Correct power or ground supply faults to the injectors
  • Repair or replace the ECM/PCM, and reprogram if required

Questions and answers

What does P0274 mean?

The ECM saw too high a signal in the cylinder 5 injector circuit. The injector or its wiring is the usual culprit, and the ECM itself is less common.

Can I drive with P0274?

Only for a short distance, such as to a shop. The engine will run rough, and misfires can damage the catalytic converter.

How do I tell a bad injector from a wiring problem?

Measure the injector resistance and inspect the connector and harness. You can also swap the injector with a neighbor: if the fault moves to that cylinder, the injector is 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.