Injector Circuit Malfunction - Cylinder 1
The P0201 code means the vehicle's onboard diagnostic system has detected: Injector Circuit Malfunction - Cylinder 1. This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- medium
- Estimated cost
- $25-$50 for wiring repair; $100-$400 for injector
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Common Symptoms
- Check Engine Light on
- Misfire on cylinder 1
- Rough idle
- Power loss
- Fuel smell from exhaust
Probable Causes (Ranked by Likelihood)
- Open or short in cylinder 1 injector circuit Very High
- Failed cylinder 1 fuel injector High
- Damaged wiring or connector at cylinder 1 injector High
- PCM driver fault for cylinder 1 injector Moderate
Step-by-Step Diagnostic Procedure
-
Identify cylinder 1 location on your engine.
-
Plug a NOID light into the cylinder 1 injector connector. Crank the engine and observe flashing.
-
If NOID flashes, the PCM driver is OK. Test the injector resistance (should be 11-17 ohms high-impedance).
-
No NOID flash: check wiring from injector to PCM for breaks or shorts.
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Replace injector if resistance is out of spec or if it leaks fuel with no electrical pulse.
Common Fixes by Vehicle
What techs usually find when diagnosing P0201 on specific vehicles — tap your vehicle for the fix and the exact part:
2009-2020 Ford F-150/Explorer 3.5L EcoBoost Moderate DIY
Cylinder 1 fuel injector circuit malfunction. Check the injector connector for backed-out pins or corrosion. Measure injector resistance -- should be 11-15 ohms. If open or shorted, replace the injector. On EcoBoost engines, carbon buildup on direct injector tips causes sticking. Ford TSB 14-0134 covers injector service procedures.
Labor: 1-2 hours2007-2017 Toyota Camry 2.5L Moderate DIY
Injector 1 circuit open or shorted. Check the injector connector first for corrosion or damage. Measure injector coil resistance -- should be 11-16 ohms. If the resistance is correct, check the wiring from the ECU to the injector for an open or short circuit. Replace the injector with Denso 23250-28080 if coil resistance is out of spec.
Labor: 1-1.5 hours2010-2020 Chevrolet Silverado/GMC Sierra 5.3L Moderate DIY
Cylinder 1 injector circuit fault. Check the injector connector and measure resistance (should be 11-13 ohms). If the connector has oil contamination from a valve cover leak, clean and reseal. If resistance is out of spec, replace with ACDelco 217-3449. Swap the injector with another cylinder to confirm the fault follows the injector.
Labor: 1-2 hoursFrequently Asked Questions
Should I replace all injectors if one fails?
Not necessarily. If the injector failed due to contamination or electrical damage, replacing only the failed unit is fine. If the engine has very high mileage and poor maintenance history, a set replacement may be more cost-effective.
Sources
This page is built from documented references. Verify against your own service info before repair work.
P0201 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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