Fuel and air

P0268 — Cylinder 3 Fuel Injector Circuit High

Severity: medium Drive with care, to a shop

What P0268 means

The engine control module fires the cylinder 3 injector by switching its circuit to ground and monitors the voltage and current in that circuit. P0268 is set when the reading is higher than expected, which can come from an open circuit, high resistance, a short to voltage or a failing injector driver. The injector may then fail to open properly.

Symptoms

  • Check Engine light on
  • Rough idle
  • Cylinder 3 misfire
  • Loss of power and sluggish acceleration
  • Higher fuel consumption
  • Engine shaking under load
  • Raw fuel smell from the exhaust

Possible causes

  1. Faulty injector (internal short or high coil resistance)
  2. Damaged or corroded injector wiring or connector
  3. Open circuit or poor connection in the injector wiring
  4. Injector control wire shorted to battery voltage
  5. Failed injector driver in the ECM
  6. Low battery voltage or a poor ground

How to diagnose

  1. Scan for codes and freeze frame data, and note any other injector or misfire codes.
  2. Inspect the cylinder 3 injector connector and harness for chafing, melting, corrosion or moisture.
  3. Test battery condition and system voltage, and check engine ground connections.
  4. Measure the injector coil resistance and compare it to the spec for your engine and to the other injectors.
  5. Check the wire from the injector connector to the ECM for opens and shorts to voltage or ground.
  6. Check for a driver pulse at the injector with a noid light or scope.
  7. Swap the injector with a neighbor: if the problem follows it, the injector is bad.
  8. Check fuel pressure and fuel trims; suspect the ECM last.

Common fixes

  • Replace the faulty cylinder 3 injector
  • Repair the wiring or replace the damaged connector
  • Clean the terminals and restore a solid ground
  • Replace or reprogram the ECM if the driver fault is confirmed
  • Clear the code and road test to confirm it does not return

Questions and answers

What does P0268 mean?

The ECM detected a high voltage or current signal in the cylinder 3 injector circuit. The usual culprits are the injector itself, its wiring or its connector.

Can I drive with P0268?

Only briefly and to a shop. Misfires can damage the catalytic converter and waste fuel, and if the Check Engine light flashes you should stop driving.

How do I tell an injector problem from an ECM problem?

Measure the injector resistance and test the wiring to the ECM, then swap the injector with a neighbor. If the fault moves to another cylinder, the injector is at fault.

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.