What Does P0268 Mean?
The ECM has detected an excessively high voltage or current in the cylinder 3 fuel injector circuit. This indicates either a short to voltage in the wiring, a malfunctioning injector driver in the ECM, or an injector with abnormally low resistance. On diesel engines, this may cause cylinder 3 to receive excessive fuel, leading to rough running, white/black smoke, or knock from that cylinder.
Common Causes
35%
Short to battery voltage in the cylinder 3 injector wiring harness
30%
Faulty cylinder 3 fuel injector with internal short (low resistance)
15%
Corroded or damaged connector pins at the cylinder 3 injector
12%
ECM injector driver circuit fault causing excessive current output
8%
Cross-wired injector circuit contacting adjacent cylinder's circuit
Diagnostic Steps
1
Measure cylinder 3 injector resistance with a DVOM at the connector — typical values range from 0.5-1.5 ohms (piezo diesel) or 11-16 ohms (gasoline port injection). Significantly low resistance confirms a shorted injector.
2
Disconnect the cylinder 3 injector and check the harness for shorts to voltage — measure from each injector pin to battery positive. Any reading below OL indicates a short to power.
3
Inspect the cylinder 3 injector connector for evidence of heat damage, corrosion, fuel contamination, or spread/damaged pins that could cause abnormal circuit behavior.
4
Compare the injector current waveform of cylinder 3 against a known-good cylinder using a current clamp — the peak current and hold current should be virtually identical.
5
If wiring and injector test good, swap the cylinder 3 injector with an adjacent cylinder and clear codes — if the code follows the injector, replace it; if it stays at cylinder 3, suspect the ECM driver.
Estimated Repair Cost
$100 - $800
Parts + labor, varies by vehicle and location
The ECM has detected an excessively high voltage or current in the cylinder 3 fuel injector circuit. This indicates either a short to voltage in the wiring, a malfunctioning injector driver in the ECM, or an injector with abnormally low resistance. On diesel engines, this may cause cylinder 3 to rec...
The most common cause of P0268 (Cylinder 3 Injector Circuit High) is: Short to battery voltage in the cylinder 3 injector wiring harness
Typical repair costs for P0268 range from $100 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
An injector circuit stuck high can cause overfueling on cylinder 3, potentially leading to engine knock, catalytic converter damage, or in extreme cases hydrolocking. Avoid heavy loads and have it repaired promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0268 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Injection System
Difficulty
Type
Generic (SAE)
Recommended Tools
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