P0277
Cylinder 6 Injector Circuit High
When a vehicle powertrain module registers the fault code P0277, it points directly to an internal system malfunction identified as "Cylinder 6 Injector Circuit High". Operating your engine under this condition may degrade long-term fuel maps.
Driver's Summary
Your vehicle's computer logged P0277 after detecting a malfunction in the cylinder 6 injector circuit high system. Drivers typically experience flashing check engine light, poor fuel economy when this code is active. Stop driving as soon as it is safe to do so. This fault can lead to expensive secondary damage if left unaddressed.
Symptoms
Flashing check engine light, poor fuel economy
Common Causes
- Short to power in Cyl 6 injector circuit
- Failed fuel injector
- Damaged wiring near hot exhaust components
- Internal PCM short
How to Fix
- 1 Locate and fix shorted wire
- 2 Replace Cyl 6 injector
- 3 Reroute wiring away from heat
- 4 Test PCM voltage
Technical Explanation
Detection of P0277 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?
Driving with an active P0277 fault risks accelerating damage to short to power in cyl 6 injector circuit and related components. The longer the fault persists, the more expensive the eventual repair becomes — what starts as a sensor or solenoid issue can escalate to major mechanical failure.
Mechanic's Pro Tip
When diagnosing P0277, always test fuel volume delivery in addition to static pressure — a pump that holds pressure at idle but delivers insufficient volume under load will cause the fault only during acceleration or high demand, making it difficult to replicate in the driveway. Use a fuel pressure gauge with a volume outlet port: a healthy pump should deliver at least 1 liter per minute. Replace the fuel filter first; it's the cheapest test and solves the fault in a significant percentage of cases.
Injector: 200 - 450