P0210 – Injector Circuit/Open Cylinder 10

DTC P0210 is an ISO/SAE controlled powertrain code that indicates an electrical problem in the fuel injector circuit for cylinder 10. The official definition is “Injector Circuit/Open Cylinder 10,” which is specific: the engine control module (ECM/PCM) has detected an open circuit (or a condition that appears electrically open) in the wiring, connector, or injector coil associated with injector #10. When that circuit is open, the injector may not be able to deliver fuel as commanded, which can affect combustion on cylinder 10 and overall drivability. Because the fault type is Circuit/Open, accurate diagnosis focuses on electrical integrity—power feed, control/driver circuit behavior, and terminal fit—before replacing components.

P0210 Quick Answer

P0210 – Injector Circuit/Open Cylinder 10 means the ECM/PCM detected an open circuit condition in the injector electrical circuit for cylinder 10. Start with a careful check of injector #10 connector seating and terminal condition, then verify injector power supply and the ECM/PCM control (driver) circuit before replacing the injector or control module.

What Does P0210 Mean?

P0210 is defined as “Injector Circuit/Open Cylinder 10”. This means the engine controller detected that the electrical circuit for the fuel injector on cylinder 10 is open or not responding as an electrically complete injector circuit should when the injector is commanded.

An “open” can be caused by a disconnected connector, a backed-out or corroded terminal, a broken wire, a failed splice, or an injector with an internally open coil. Importantly, this code identifies the fault as an electrical circuit open related to injector #10; it does not, by itself, confirm a mechanical fuel delivery issue or prove that the injector is definitively bad.

Theory of Operation

Fuel injectors are electrically actuated valves. In many designs, injectors share a common power feed (often battery voltage with the key on), while the ECM/PCM controls each injector individually through a dedicated control circuit (often a low-side driver that switches the circuit to ground in pulses). Those pulses energize the injector coil, allowing the injector to open for a calculated duration to deliver fuel.

For cylinder 10 to receive correct fueling, the injector circuit must be electrically complete: power must reach the injector, the control side must be able to switch as commanded, and current must be able to flow through the injector coil. P0210 sets when the controller’s monitoring logic indicates an open circuit condition for injector #10—meaning current flow or expected electrical behavior is missing or outside the expected range during operation.

Symptoms

• Rough idle or unstable idle quality
• Noticeable misfire or shake that may correlate with cylinder 10 contribution loss
• Reduced engine power or hesitation, especially under load
• Hard starting or extended crank (severity varies by application and operating conditions)
• Illuminated MIL (Check Engine Light); in some cases misfire-related warnings may accompany the condition
• Additional related DTCs may be present (for example, misfire or fuel trim codes), depending on the vehicle’s monitoring strategy

Common Causes

• Injector #10 connector unplugged, not fully seated, or locking tab/retainer not securing properly
• Terminal damage at injector #10 connector (spread pins, backed-out terminals, poor pin tension)
• Corrosion or moisture intrusion at the injector connector or in-line harness connector
• Open circuit in injector #10 control wire between the ECM/PCM and the injector connector
• Open circuit in injector power feed to cylinder 10 (blown fuse, failed relay, open splice, damaged feed wire)
• Harness damage from rubbing/chafing near brackets, valve covers, intake components, or the fuel rail leading to an open conductor
• Injector #10 internal coil open (injector winding failure resulting in no current flow)
• ECM/PCM injector driver fault (consider only after power, ground, wiring integrity, and injector coil checks are verified)

Diagnosis Steps

Tools needed: OBD-II scan tool with data stream access (and bidirectional controls if available), wiring diagram for injector #10 identification, DVOM (digital volt/ohm meter), noid light or injector pulse tester (or lab scope if available), back-probe/terminal test probes, and a fused jumper or fused test light for loaded circuit checks.

1. Verify the code and capture data. Confirm P0210 is present (stored or pending) and record freeze-frame data (RPM, load, coolant temperature, system voltage). Check for additional DTCs that may affect diagnosis (battery voltage, module power supply, misfire-related codes).
2. Confirm cylinder 10 and injector location. Use service information to correctly identify cylinder numbering and injector #10 connector. Misidentification can lead to testing the wrong circuit.
3. Perform a visual inspection of injector #10 and harness routing. Look for a disconnected connector, broken lock, oil contamination, pinched harness sections, or areas where the loom may be stretched or rubbing. Gently tug on the wires near the connector to check for broken conductors under insulation.
4. Check injector power supply integrity. With key on, verify the injector feed voltage at injector #10 (back-probe where appropriate). If voltage is missing, inspect the related fuse(s), relay(s), and power distribution points, and trace the open through splices and harness segments.
5. Check for injector control (driver) activity. Use a noid light, injector pulse tester, or lab scope on injector #10 control circuit while cranking or idling (as applicable). Confirm whether the ECM/PCM is providing a switching signal to the injector circuit.
6. Measure injector #10 coil resistance and compare. With the circuit powered down and connectors safely disconnected, measure injector #10 resistance and compare it to other injectors on the same engine at the same temperature. An open reading (or a clear outlier compared to the others) supports an injector internal open circuit.
7. Load-test the control circuit for an open. If the scan tool supports injector actuation, command injector #10 on/off and verify the control circuit can carry load. Where appropriate, use a fused test light method or similar loaded test (following service information) to reveal opens/high resistance that may not show up with simple continuity tests.
8. Wiggle test for intermittents while monitoring the signal. While observing the noid light/scope or scan tool data, gently move the injector #10 connector and nearby harness sections. A change indicates a poor connection, broken conductor, or terminal fit issue consistent with an open circuit condition.
9. Perform targeted continuity checks only after loaded testing. With connectors unplugged (including the ECM/PCM connector as required by service information), check end-to-end continuity of the injector #10 control wire and power feed, and verify there is no unintended short to power or ground. Repair opens, damaged wiring, or terminal issues found.
10. Confirm the repair. Reconnect components, clear DTCs, and run the engine under conditions similar to the freeze frame. Verify P0210 does not return (pending or stored) and confirm stable operation. Recheck for any additional codes that may have resulted from the original open-circuit condition.

Professional tip: Prioritize loaded electrical testing (voltage checks and voltage-drop/load tests) over continuity alone. A circuit can show continuity at rest yet behave like an open under vibration, heat, or current draw due to poor terminal tension, corrosion, or a partially broken conductor.

Possible Fixes

• Reseat injector #10 connector and ensure the lock/retainer fully engages
• Repair or replace damaged injector #10 connector terminals (backed-out pins, poor tension, corrosion)
• Repair open wiring in the injector #10 power feed or control circuit (broken wire, damaged splice, harness damage)
• Replace a blown injector power supply fuse or faulty relay after correcting the underlying cause
• Replace injector #10 if testing confirms an internal injector coil open
• Address ECM/PCM power/ground issues that could prevent proper driver operation (only if verified by testing)
• Replace the ECM/PCM only after confirming wiring integrity and demonstrating the driver cannot operate a known-good circuit per service procedures

Can I Still Drive With P0210?

Driving with P0210 is not recommended beyond what is necessary to diagnose and repair, because an injector circuit open on cylinder 10 can cause misfiring, rough operation, and reduced power. If the engine is running poorly, continued operation can increase stress on the engine and exhaust system. If the vehicle is difficult to keep running, shakes heavily, or exhibits severe drivability issues, stop driving and diagnose the injector circuit/open condition promptly.

How Serious Is This Code?

P0210 should be treated as a serious electrical fault because it indicates an open circuit affecting fuel delivery control for cylinder 10. An injector circuit open can lead to persistent misfire and unstable combustion, which may quickly degrade overall performance and can contribute to additional problems if operation continues. The seriousness increases if the fault is constant rather than intermittent, or if the engine runs noticeably rough, because the cylinder may not be fueled correctly when the circuit is open.

Common Misdiagnoses

Common mistakes include replacing injector #10 immediately without confirming the circuit is open (for example, a loose connector, backed-out terminal, or broken wire), assuming the ECM/PCM is defective before verifying power supply and wiring integrity, and relying only on continuity checks instead of verifying voltage and signal behavior under load. Another misdiagnosis is testing the wrong injector due to incorrect cylinder numbering, which can result in unnecessary parts replacement and unresolved P0210.

Most Likely Fix

The most likely fix for P0210 is restoring electrical continuity in the injector #10 circuit by correcting a connector or wiring open—such as reseating the injector connector, repairing damaged terminals, or repairing an open in the harness (power feed or control circuit). If circuit integrity and proper command are confirmed at the connector and the injector coil is proven open, replacing injector #10 becomes the appropriate corrective action.

Repair Costs

Repair cost depends on whether the confirmed root cause is a sensor, wiring, connector issue, or control module problem. Verify the fault electrically before replacing parts.

Last updated: April 1, 2026