P0261 on Ford: How to Diagnose & Fix
Cylinder 1 Injector Circuit Low
1 Ford model · 1 documented issue · $350-$1,100 repair
P0261 on Ford by model: symptoms, diagnosis and fix
The 6.0L Power Stroke's Fuel Injection Control Module sits on top of the driver-side valve cover and must deliver a 48-volt pulse to fire each HEUI injector. The module is heat-soaked in that location and its internal power supply degrades over time; it is also killed outright by weak batteries or a failing charging system, because the boost circuit is damaged when supply voltage sags below about 12.6 volts during cranking. As FICM main power output drops below roughly 46 volts, the injector solenoids begin to open late, producing hard starting, rough cold running and white smoke. A dying FICM can subsequently damage injectors. F-350s with two batteries that are not replaced as a matched pair are the classic case.
Common Symptoms
- Extended cranking / hard start, worse when cold
- Rough idle and misfire for the first minutes after start
- White smoke at startup
- No-start with normal cranking speed
- FICM main power below 47 volts on a scan tool
- Repeat injector failures
How to Fix
Read FICM main/logic/vehicle power with a scan tool (IDS or a capable aftermarket tool) at key-on and while cranking. Anything below about 47.5 volts at idle indicates a failing module. Fix the batteries and charging system FIRST, then have the FICM rebuilt with upgraded power-supply components (common, and far cheaper than a new module) or install a remanufactured unit. No recall covers this. Replacing the FICM without correcting weak batteries will kill the new module too.
Sources for this issue (3)
P0261 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0261 mean on a Ford?
P0261 stands for "Cylinder 1 Injector Circuit Low." The PCM detected low voltage (short to ground or open on the power side) in the cylinder 1 fuel injector control circuit. The injector cannot be properly energized, leading to a misfire on that cylinder. On Ford it is documented across 1 model: F-350.
What are the most common causes of P0261?
The most common causes of P0261 are: Short to ground in cylinder 1 injector wiring, Open on the injector power feed, Faulty cylinder 1 injector, Loose or corroded connector, PCM injector driver fault. The specific cause varies by vehicle.
How much does it cost to fix P0261 on a Ford?
Published repair estimates on Ford range from $350 to $1,100 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0261 on a different make?
View P0261 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.