P0268
Cylinder 3 Injector Circuit High
The appearance of the standard OBD2 trouble fault code P0268 is an indicator that your vehicle ECU triggered a threshold alert for "Cylinder 3 Injector Circuit High". Understanding the root component breakdown helps avoid expensive diagnostic fees.
Driver's Summary
Storing code P0268 is your car's way of telling you something is wrong with the cylinder 3 injector circuit high. Drivers typically experience engine misfire, raw fuel smell from exhaust when this code is active. This is not a code to ignore — the underlying fault can rapidly worsen and lead to costly repairs if driving continues.
Symptoms
Engine misfire, raw fuel smell from exhaust
Common Causes
- Short to voltage on injector control wire
- Internally failed injector coil
- Wiring harness rubbed through insulation
- PCM fault
How to Fix
- 1 Inspect and repair wiring harness
- 2 Replace Cylinder 3 fuel injector
- 3 Tape and secure rubbed wiring
- 4 Test PCM
Technical Explanation
Detection of P0268 occurs when the ECM cross-references multiple sensor inputs and determines that the reported values are physically inconsistent or out-of-range. Misfire rate is counted per cylinder over rolling windows and compared against two thresholds: a catalyst-damaging rate (triggers flashing MIL) and an emissions-exceeding rate (triggers solid MIL). The PCM logs which cylinder is misfiring based on crankshaft position at the time of each detected event. The fault remains stored in memory even after the MIL is cleared; it becomes a confirmed DTC after failing two consecutive drive cycles, and the PCM logs a freeze frame record of the engine's exact operating state at the moment of detection.
Is It Safe to Drive?
This fault carries real mechanical risk. The root causes — including short to voltage on injector control wire — can trigger a chain reaction of component failures if the vehicle continues to be driven. Have it towed or drive directly to a shop without delay.
Mechanic's Pro Tip
The fastest isolation technique for P0268 is the coil swap test: move the ignition coil from the affected cylinder to a neighboring cylinder and clear the code. If the misfire follows the coil, it's the coil. If it stays on the same cylinder, focus on the spark plug, injector, or compression. Never replace coils without also replacing the spark plug in that cylinder — a fouled plug will kill a new coil within weeks.
Injector replacement: $150 - $400