Comprehensive diagnostic guide for P0211 Injector Cylinder 11 - Open Circuit

• The open-source definition provided (MIT) identifies P0211 as " Injector cylinder 11 - circuit open." This is one documented interpretation of P0211 in an open-code repository. In official OEM practice, P0211 is a cylinder-specific injector fault; mappings and cylinder numbers can vary by engine family. When diagnosing, always correlate with the vehicle's service information for cylinder numbering and injector wiring schematics.

• Context from standard OBD-II references:

  • OBD-II uses Diagnostic Trouble Codes to signal faults in powertrain and related systems; powertrain codes (P-codes) cover fuel, ignition, and emission-related subsystems.
  • The diagnostic approach for P-codes is to verify electrical/electronic faults, then mechanical/fuel system issues, consistent with how P0211 would typically be treated as an injector-circuit fault.

• For general approach to DTC-driven diagnostics, refer to the OBD-II overview and emission-testing context for how codes are used to drive fault isolation.

What This Code Means

• Indication: Injector cylinder 11 - open/open circuit or failure within the injector circuit for cylinder 11 (per the open-source code definition). In practice, "open circuit" means the PCM is not seeing current flow or a commanded injector activation for cylinder 11.
• Effects: If cylinder 11 injector is truly open, that cylinder does not receive fuel as commanded, which can cause misfire, rough idle, reduced power, and potential drivability complaints. Other cylinders and fuel system behavior may be unaffected, but engine performance can degrade when a cylinder is out.

Common real-world user symptom descriptions you may see

• Rough idle or vibration when the engine is cold or at idle, with the check engine light on.
• Intermittent or persistent misfire indication for cylinder 11, or a general misfire pattern that points to a single cylinder.
• Degraded engine power or hesitation under load when the vehicle demands more fuel.
• Noticeable fuel smell during startup or when running; in some cases, fuel trims may be high trying to compensate for the missing injector contribution.
• Poor fuel economy if misfire persists as the engine runs on fewer than eight healthy cylinders.
  Note: These symptom sets reflect typical customer-reported experiences and are consistent with how injector circuit faults present in practice.

Probable Causes

• Injector 11 circuit issues (most common): injector coil/open or internal fault, or an intermittent open circuit in wiring to injector 11. 40-50%
• Wiring harness / connector problem to injector 11 (damaged insulation, corrosion, poor connection, routed through harness shoulders, etc.). 25-30%
• PCM/driver fault (injector drive transistor or output stage within the PCM/ECU). 10-15%
• Power supply or ground integrity problems affecting injectors or PCM (battery, ground strap faults, or related EMI/common-mode issues). 5-10%
• Mechanical or fuel-system anomalies that mimic or contribute to an injector-open symptom (extremely low probability for true open-circuit fault, more common as contributing factors rather than the sole cause). 0-5%

Safety Considerations

• Relieve fuel system pressure before disconnecting fuel lines or injectors.
• Disconnect the battery or disable the fuel pump while performing heavy wiring work or injector replacement to prevent accidental firing.
• Use proper PPE (eye protection, gloves) and follow all shop safety procedures when working with fuel systems and high-energy electrical components.

Repair Actions

• Replace the faulty injector 11 if the electrical tests or swap test indicate the injector itself is defective.
• Repair or replace damaged injector wiring harness or connectors; correct poor connections and secure harness routing to prevent chafing.
• Repair/replace PCM driver or update firmware as recommended by the OEM if electrical drive signal faults are confirmed and no injector/wiring fault exists.
• Verify fuel system integrity (pressure spec, filter condition) and repair any related issues if they contribute to misfire or improper injector operation.
• Re-test to confirm the fault is resolved and that no new codes appear.

Documentation

• DTC code(s) and freeze-frame data.
• Symptom descriptions before and after repair.
• Electrical test results (injector resistance, supply voltage, PWM waveform if available).
• Injector swap results if performed.
• Service actions completed (injector replacement, wiring repairs, PCM software update, etc.).
• Verification data showing code clear and symptom resolution.

This diagnostic guide was generated using verified reference data:

• Wikipedia Technical Articles: OBD-II
• Open-Source OBD2 Data: N/A (MIT)

Content synthesized from these sources to provide accurate, real-world diagnostic guidance.

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