Cylinder 1 Injector Circuit Low
The P0261 code means the vehicle's onboard diagnostic system has detected: Cylinder 1 Injector Circuit Low. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $100 - $400 (parts and labor)
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Common Symptoms
- Engine misfire on cylinder 1
- Rough idle
- Check Engine Light illuminated
- Reduced power and poor acceleration
- Strong fuel smell from exhaust
Probable Causes (Ranked by Likelihood)
- Short to ground in cylinder 1 injector wiring Very High
- Faulty cylinder 1 fuel injector (shorted coil) High
- Corroded injector connector pins High
- Damaged wiring harness near injector Moderate
- PCM injector driver circuit failure Low
Step-by-Step Diagnostic Procedure
-
Measure cylinder 1 injector resistance -- should be 11-18 ohms for high-impedance injectors; below spec indicates a shorted coil
-
Check for short to ground by testing continuity between the injector signal wire and engine ground with injector disconnected
-
Swap cylinder 1 injector with cylinder 2 and clear codes -- if the code follows the injector, replace it
-
Inspect the injector wiring harness for chafed or melted insulation near exhaust components
-
If wiring and injector test good, test the PCM injector driver output with a noid light
Common Fixes by Vehicle
What techs usually find when diagnosing P0261 on specific vehicles — tap your vehicle for the fix and the exact part:
2005-2018 Ford F-150/Escape/Explorer moderate DIY
Cylinder 1 injector circuit low means the PCM detects low current draw from the #1 fuel injector. On Ford engines, the most common cause is a corroded injector connector. Check the connector at injector #1 for pushed-out pins, corrosion, or oil contamination. If the connector is clean, swap injector #1 with injector #2 and clear codes -- if the code moves to P0264, the injector is bad. If the code stays at P0261, the wiring is the issue.
Labor: 30 min - 1 hour2008-2019 GM Silverado/Sierra/Malibu moderate DIY
On GM engines, P0261 can be caused by a failed injector, a wiring fault, or a PCM driver circuit issue. Start by checking the injector resistance -- it should be 11-14 ohms on most GM port-injected engines. If resistance is low (under 8 ohms), the injector has a shorted coil and needs replacement. If resistance is normal, check the wiring from the PCM connector to injector #1 for continuity.
Labor: 30 min - 1 hour2005-2018 Toyota Camry/Corolla/RAV4 moderate DIY
Toyota fuel injector circuit low codes are less common than on domestic vehicles. Check the injector connector for oil fouling -- leaking valve cover gaskets drip oil into the injector connectors. Clean the connector with electrical contact cleaner and replace the valve cover gasket to prevent recurrence. If the injector coil is open or shorted, replace the injector with a Denso OEM unit.
Labor: 30 min - 1 hourFrequently Asked Questions
Can I drive with code P0261?
You can drive short distances, but the engine will run on fewer cylinders causing rough operation and potential catalytic converter damage from unburned fuel.
What does injector circuit low mean?
It means the PCM detects lower than expected voltage or resistance in the fuel injector circuit for cylinder 1, usually caused by a short to ground in the wiring or a shorted injector coil.
Can I swap injectors to test?
Yes. Swapping the suspect injector with one from another cylinder is an excellent diagnostic technique. If the code moves to the other cylinder, the injector is faulty.
Sources
This page is built from documented references. Verify against your own service info before repair work.
P0261 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
See All Codes & Fixes for Your Vehicle
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