Injector Circuit Malfunction - Cylinder 3
The P0203 code means the vehicle's onboard diagnostic system has detected: Injector Circuit Malfunction - Cylinder 3. This is a serious severity code.
- Keep driving?
- Limited driving only
- DIY difficulty
- medium
- Estimated cost
- $25-$400
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What Are the Symptoms of P0203?
- Check Engine Light on
- Misfire on cylinder 3
- Rough idle
- Power loss
- Fuel smell
What Causes P0203? (Most Likely First)
- Wiring fault at cylinder 3 injector Very High
- Failed cylinder 3 injector High
- PCM driver fault for cylinder 3 Moderate
Can I Still Drive with P0203?
Limited driving only. P0203 is rated serious severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Common Fixes by Vehicle
What techs usually find when diagnosing P0203 on specific vehicles — tap your vehicle for the fix and the exact part:
2009-2020 Ford F-150/Expedition 3.5L EcoBoost Moderate DIY
Cylinder 3 injector circuit malfunction. On the EcoBoost, direct injectors fail more often than port injectors due to carbon buildup on the tips. Check resistance (11-15 ohms) and swap with another cylinder to confirm. If the circuit fault follows the injector, replace it. If it stays on cylinder 3, the wiring or PCM driver is the issue.
Labor: 1-2 hours2008-2019 Honda Accord/CR-V 2.4L Moderate DIY
Cylinder 3 injector circuit fault. Check the injector connector for oil contamination from valve cover gasket seepage. Measure injector resistance (should be 11-13 ohms on the K24). If resistance is out of spec, replace with an OE-quality Denso unit. Also check the injector driver circuit by backprobing the connector while cranking. Confirm the exact part for your year and engine with a retailer's fitment lookup or your VIN before ordering - these applications split by engine and build date.
Labor: 1 hour2010-2020 Chevrolet Silverado/Tahoe 5.3L Moderate DIY
Cylinder 3 injector circuit malfunction. On the 5.3L, check the injector harness connector first -- vibration can loosen them. Measure coil resistance (11-13 ohms). If the injector is good, swap it with another cylinder to verify. Check the PCM injector driver circuit by measuring voltage pulse at the connector while cranking.
Labor: 1-1.5 hoursFrequently Asked Questions
Does a cylinder 3 injector fault always cause a misfire?
An open injector circuit (no fuel) will cause a misfire. A shorted circuit may cause intermittent issues or just the circuit code without a misfire, depending on whether the injector still opens partially.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0203?
-
NOID light test on cylinder 3 injector.
-
Resistance test on cylinder 3 injector.
-
Wiring continuity check.
-
Injector balance test.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
P0203 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:
Which Vehicles Commonly Get P0203?
- GM 3.1L and 3.4L V6 engines
- Ford 3.0L V6 Ranger and Taurus
- Dodge 3.7L and 4.7L V6/V8
- Toyota 3.5L V6
- Honda 3.5L V6 Odyssey
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