P0210 - Injector Cylinder 10 Open Circuit OBD-II DTC

P0210 - Injector Cylinder 10 Open Circuit (OBD-II DTC)

Overview

• What it means: The engine control module (ECM/PCM) has detected an open circuit condition on the fuel injector for cylinder 10. In practical terms, cylinder 10 is not receiving fuel because the injector coil circuit is not completing (no current flow when commanded).
• Context: P0210 is part of the injector circuit/diagnostic trouble code family within the OBD-II powertrain codes. DTCs are used by the vehicle's onboard diagnostics to monitor systems and flag faults when parameters are out of expected range. See general OBD-II DTC discussions for how these codes are produced and interpreted.
• Source note: The open-source listing explicitly identifies a cylinder-10 injector open-circuit condition as a code indication. As with many injector-related codes, it suggests a fault in the injector circuit rather than only a mechanical injector failure. Citations: OBD-II DTC background, and the open-source injector definition for cylinder 10.

Symptoms you'll typically see (patient complaints you'd hear)

• MIL (Check Engine Light) illuminated with P0210 stored or pending.

• Rough idle or irregular engine running, especially when idle or under light load.

• Intermittent or consistent misfire indications on cylinder 10; vehicle may run smoother when the engine is governed to a single cylinder loss (roughly felt as a stumble or hesitation).

• Possible drop in engine power or poor acceleration due to one-cylinder lean/out of fuel.

• Increased fuel consumption or rough engine behavior at certain RPMs.

• In some cases, you may see a misfire-related code in P030X family (e.g., P03010 for cylinder 10 misfire) if the misfire is severe or the OEM code mapping associates misfire with the cylinder affected.

• Cylinder-specific injector code: The verified open-source entry lists "Injector Cylinder 10 - Open Circuit" as a code description, indicating the cylinder 10 injector circuit is open (no current) as the fault condition for P0210 in that repository. This aligns with the idea of an injector circuit fault rather than strictly a mechanical injector failure. Source: OBD2 CODE DEFINITIONS.

Probable Causes

• Injector 10 coil/open circuit (internal injector fault): 45-60%
  • Most common scenario when the circuit cannot complete and the ECM sees no current on the injector. An open injector coil or internal fault can produce the open-circuit condition.
• Wiring harness issue to injector 10 (open or damaged wire, broken pin, cracked insulation, poor connector): 25-35%
  • Damaged wiring or corroded/loose connectors commonly cause intermittent or permanent open circuits.
• Injector driver/PCM output fault (ECM/PCM injector drive circuit failure): 5-15%
  • A failed transistor/output in the PCM or a PCB fault can prevent energizing the injector, producing an open-circuit reading on that channel.
• Faulty injector ground or power supply to that injector (fused circuit, power supply issue): 5-10%
  • A loss of proper supply or grounding can manifest as an apparent open circuit to the injector.
• Other related wiring/connector issues (e.g., poor splice, cross-talk, high resistance in the injector circuit): less than 5%
  • Less frequent but possible in complex harness routes.

Safety and precautionary notes

• Fuel system hazards: High-pressure fuel system can leak and ignite. Relieve fuel pressure before servicing injectors. Work in a well-ventilated area away from ignition sources.
• Electrical safety: Disconnect the battery before disconnecting any fuel injector harness or wiring to avoid sparks, and to protect the ECM/PCM.
• PPE: Safety glasses, gloves, and appropriate hot-work precautions when dealing with engine components and fuel lines.
• Polyethylene gloves and eye protection are recommended when handling fuel system components.

Diagnostic Approach

1) Confirm and document the fault

• Use an OBD-II scanner to confirm P0210 with the freeze-frame data. Note any related codes (P03010 for cylinder 10 misfire, or other injector codes for nearby cylinders).
• Check whether the misfire/misbehavior correlates to cylinder 10 and whether the pattern follows a single-cylinder issue or a broader fuel/injection problem.
• Note driving conditions from freeze-frame data (engine RPM, load, temperature, fuel trim). This helps correlate symptoms with injector behavior.

2) Visual and basic electrical inspection

• Inspect the injector 10 harness connector and wiring for obvious damage, moisture, corrosion, or loose pins.
• Check for chafed or pinched wires along the injector harness path (engine harness paths near intake, fuel rails, or cylinder head).
• Check related fuses/relays that supply power to the injector circuit (if the vehicle's wiring diagram indicates a fused supply for the injector rail or ECU outputs).

3) Inspect injector coil resistance (DC resistance test)

• With the ignition OFF and the battery disconnected (or after following safe procedure to avoid sparks), measure the resistance of injector 10 across its two pins.
• Compare measured resistance to the manufacturer's specification for that injector. A very high resistance (approaching infinite) indicates an open coil/injector fault; deviations (too low or wildly out of spec) can indicate coil damage.
• If resistance is out of spec, replace the injector. If resistance is within spec but P0210 persists, go to wiring/PCM checks.

4) Power, ground, and signal integrity checks

• With ignition ON, probe injector 10 power supply (the 12V supply) at the injector connector to confirm presence of voltage when the PCM is commanded to energize the injector.
• Verify injector ground when commanded to energize (the injector should complete to ground via the PCM drive). A noid light or oscilloscope can help verify PWM signal presence and duty cycle from the PCM to injector 10.
• If no PWM signal or a constant open condition is detected, suspect the PCM output or an open circuit in the wiring between PCM and the injector.

5) Noid light test (or oscilloscope verification)

• Use a noid light targeted to injector 10 circuit to confirm PCM energizes the injector when running. If the noid light does not flash in sync with engine operation, there is a problem in the drive signal path (PCM, wiring, or connector).
• For more thorough analysis, use an oscilloscope to observe the injector drive waveform (PWM duty cycle, voltage level, and timing). An absent or erratic waveform indicates drive/wiring/PCM issues.

6) Swap or alternate-check to isolate the fault

• If possible, interchange injector 10 with another injector (same type) to see if the code follows the injector or remains on cylinder 10.
  • If the fault code moves with the injector, the injector itself is likely faulty.
  • If the fault remains on cylinder 10 despite swapping injectors, the issue is in the wiring, PCM driver, or cylinder 10 circuit path.
• If a spare injector is not readily available, consider a controlled substitution test in the same cylinder path, documenting results carefully.

7) Fuel system and related checks

• Check rail fuel pressure (static and dynamic under pressure) to ensure injector is being supplied with adequate fuel and that a lack of fuel is not the root cause of the perceived fault.
• If fuel pressure is low or inconsistent only at cylinder 10, this points toward injector or wiring/fuel rail issues rather than ECM failure.

8) PCM and control logic review

• If injector resistance and wiring tests pass and the injector is energized correctly (PWM signal present) but cylinder 10 still shows symptoms or DTC remains, suspect PCM drive channel or internal PCM fault.
• Check for software/firmware updates or manufacturer service advisories if available for injector drive channel concerns, and verify any service bulletins related to injector drive circuits.

9) Repair steps (based on findings)

• If injector 10 is confirmed open or faulty: replace injector 10 with a new or known-good injector; re-test the circuit and reinstall with proper torque specs and seals.
• If wiring is damaged or connector is poor: repair or replace wiring harness segments; clean/repair connector pins; ensure secure locking mechanisms.
• If PCM drive channel is suspected: consult vehicle manufacturer service information; reprogram or replace PCM as dictated by the fault isolation results and service bulletin guidance.
• After any repair, re-check all injector circuits (voltage, ground, and PWM signal) and confirm fuel pressure is stable.

10) Verification and retest

• Clear DTCs after repair and perform a road test under varied conditions (idle, partial throttle, full load) to verify the code does not reappear.
• Re-check fuel trims, misfire codes, and injector signals to confirm the repair has resolved the issue.

Data to collect for reporting (when you diagnose)

• DTCs present, freeze-frame data, and any related ignition/fuel system data.
• Injector 10 coil resistance value and tolerance against spec.
• Injector 10 supply voltage and ground continuity readings with ignition on and while commanded on.
• Noid light test results or scope traces showing injector drive waveform for cylinder 10.
• Injectors' swap results (if performed) and whether the code follows the injector.
• Fuel pressure readings and any relevant engine operating data.

Summary

• P0210 is an injector cylinder 10 open circuit fault; the primary fault is typically in the injector circuit (open coil, broken wire, or faulty injector).

• Symptoms often include misfire on cylinder 10, rough idle, and possible MIL illumination.

• A systematic approach-visual/wiring inspection, resistance testing, voltage/ PWM signal checks, and controlled injector swapping-helps isolate between injector, wiring, and PCM drive issues.

• Safety and proper procedure are vital when diagnosing fuel injectors due to high-pressure fuel systems and electrical harness work.

• OBD-II diagnostic trouble codes and their role in modern engine management are described in Diagnostic Trouble Codes and Powertrain Codes.

• The open-source injector definition explicitly identifies a cylinder 10 injector open-circuit condition . This supports the interpretation of P0210 as an injector-cylinder-specific circuit fault. Citations:

  • OBD-II - Diagnostic Trouble Codes
  • OBD-II - Powertrain Codes
  • Injetor cilindro 10 - circuito aberto

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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