P0268
Cylinder 3 Injector Circuit High
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The P0268 code means the PCM has detected higher-than-expected voltage in the cylinder 3 fuel injector circuit. A 'circuit high' condition typically points to a wiring short to a power source, an injector with an open or high-resistance coil, or a malfunctioning PCM driver that's stuck in the on position.
When the circuit voltage is too high, the cylinder 3 injector may not open at all (if the coil is open) or may stay continuously open (if the driver is stuck on). Both scenarios cause a misfire on that cylinder, with associated rough running, poor performance, and potential catalytic converter damage from unburned fuel or fuel flooding.
Start diagnosis by inspecting the wiring and connector for the cylinder 3 injector. Look for damaged insulation where the harness contacts metal engine parts, and check the connector pins for corrosion. A multimeter resistance check on the injector coil is the quickest way to determine if the injector has failed. Most fuel injector replacements are relatively straightforward and affordable, making this a good DIY repair for someone with basic automotive skills.
Severity
Symptoms
- •Engine misfires or runs rough
- •Check Engine Light is on or flashing
- •Reduced engine power and poor acceleration
- •Rough idle that may cause the vehicle to vibrate
- •Increased fuel consumption
Likely Causes
Damaged wiring insulation that contacts a nearby power source creates a short to battery voltage in the cylinder 3 injector circuit, causing the PCM to detect a higher-than-normal voltage reading.
An injector with an internally open or excessively high-resistance coil causes elevated voltage readings. The injector may fail to fire completely, resulting in a dead cylinder.
If the PCM driver transistor for cylinder 3 is stuck in the energized position, the injector receives continuous voltage and the PCM registers a high circuit condition.
Significant corrosion on the connector pins creates a high-resistance junction that elevates the apparent circuit voltage, particularly when the injector is commanded on and current should be flowing.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Repair shorted or damaged wiring in the cylinder 3 injector circuit
- Replace the cylinder 3 fuel injector
- Clean and repair corroded connector pins
- Test and, if necessary, replace the PCM