P0267 Code Symptoms, Causes, Diagnosis & Repair Guide Step-by-Step

Drivers first notice the check‑engine light flashing or staying on, followed by a noticeable misfire that feels like a stumble when the engine is under load. The idle may become uneven, and acceleration can feel hesitant as the engine struggles to maintain smooth power. Because the fault is tied to the injector that supplies fuel to cylinder 3, the engine’s combustion cycle is disrupted, producing the described drivability issues.

Symptoms

• Check‑engine light illuminated (often accompanied by a “Misfire Detected” sub‑code).
• Cylinder 3 misfire detected by the PCM, felt as a single‑cylinder stumble.
• Rough or uneven idle that may fluctuate between 600‑800 rpm.
• Hesitation or loss of power during light‑throttle acceleration.
• Increased fuel consumption if the condition persists, as the engine compensates for the misfire.

These signs appear because the injector’s electrical command is weaker than the PCM/ECU expects, preventing the proper amount of fuel from being delivered to cylinder 3.

Why P0267 Problems Occur

1. Faulty PCM/ECU Output Circuit

The PCM (Powertrain Control Module) generates a low‑side ground or high‑side voltage to operate the injector. Internal component failure—such as a burned driver transistor or damaged driver IC—reduces the voltage below the threshold the injector requires, triggering the “circuit low” condition.

2. Wiring Harness Defects

Corrosion, broken strands, or poor crimp connections in the injector’s power or ground wires can introduce resistance that drops the voltage. Even a minor pinched wire near the engine bay can cause the PCM’s signal to fall short of spec, resulting in P0267.

3. Connector or Pin‑out Issues

The connector at the injector or the PCM side may have bent pins, debris, or oxidation. A compromised pin prevents a solid electrical path, producing intermittent low‑circuit readings that the PCM logs as P0267.

While a defective injector itself could also cause a misfire, the P0267 definition specifically points to a low‑voltage condition, so the focus remains on the control circuit rather than the injector hardware.

Diagnostic and Repair Procedures

1. Retrieve and clear codes with a professional OBD‑II scanner. Confirm that P0267 appears consistently after a drive cycle.
2. Perform a live data scan of injector‑A voltage for cylinder 3. Expected values are typically 5 V (low‑side) or 12 V (high‑side). Readings below 4 V indicate a low‑circuit condition.
3. Inspect wiring from the PCM to the cylinder 3 injector. Look for frayed insulation, corrosion, or physical damage. Use a multimeter to measure resistance; values greater than 0.5 Ω suggest a problem.
4. Check connectors at both the PCM and injector. Clean any carbon build‑up with electrical contact cleaner, and verify that pins are straight and fully seated.
5. Bench‑test the injector (optional) by applying the specified voltage directly to confirm it operates correctly. If the injector fires, the fault lies upstream.
6. Test PCM output by back‑probing the injector control wire while the engine is cranking. If voltage is present at the wire but absent at the injector connector, the PCM driver is likely defective.
7. Repair or replace wiring/connector as needed. Re‑torque connector fasteners to manufacturer torque specifications.
8. If the PCM output remains low after wiring verification, the module requires reprogramming or replacement. A reflash may resolve software‑related voltage regulation issues; a hardware failure mandates a new PCM/ECU.

Typical labor for a complete diagnosis ranges from $120‑$180, while a PCM reflash costs $80‑$130. Replacement PCM units generally run $600‑$900 plus $200‑$300 labor, reflecting the need for VIN‑matched programming.

When Replacement Makes More Sense Than Repair

When the PCM’s injector driver circuit has failed, repairs are often temporary because the underlying semiconductor damage can recur. Replacing the module eliminates the risk of repeated low‑circuit events and restores full injector control.

Flagship One specializes in VIN‑matched control modules, providing a plug‑and‑drive solution backed by warranty. Modern control modules are complex and integrated with security and immobilizer systems; correct programming and compatibility are essential. Flagship One’s pre‑programmed units are matched to your vehicle’s VIN before shipping, ensuring immediate readiness and eliminating dealer‑only re‑coding delays.

If the PCM has suffered water intrusion, severe heat exposure, or internal component burnout, opting for a new, factory‑calibrated module is the most reliable path to restoring engine performance.

Preventive Maintenance

• Regularly inspect the injector harness during scheduled service intervals. Look for signs of wear near heat sources such as the exhaust manifold.
• Keep connector contacts clean by applying dielectric grease after cleaning; this reduces corrosion risk in the engine bay’s harsh environment.
• Avoid exposure to excessive moisture by ensuring engine‑bay seals and splash shields are intact. Water ingress is a common catalyst for PCM driver failures.
• Use a quality scan tool during routine emissions checks to catch low‑circuit anomalies before they trigger a misfire. Early detection allows wiring repairs before the PCM is stressed.
• Follow manufacturer service bulletins that may address known PCM voltage‑regulation updates; applying recommended software revisions can prevent low‑circuit codes.