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DTC codes / P02xx · Fuel and air metering (injector circuits) / P02F6

P02F6Cylinder 9 Injector Circuit Range/Performance

P02F6 means the powertrain control module (PCM) has detected that the electrical circuit for cylinder 9's fuel injector is not performing within its expected range, which usually indicates a wiring, connector, or injector coil problem rather than a mechanical engine fault. The PCM monitors injector circuit voltage and current during operation and sets this code when the measured values fall outside the calibrated window for a calibrated period of time.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering (injector circuits)

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • A noticeable engine misfire or rough running condition, especially under load or at idle
  • Reduced engine power or a limp-home mode in some vehicles
  • Shaking or vibration felt through the steering wheel or seat
  • A faint fuel odor from the exhaust due to unburned fuel from the affected cylinder
  • Slightly worse fuel economy over time if the misfire is persistent

Common causes, most likely first

  1. Faulty cylinder 9 fuel injector with an internally shorted or open coil
  2. Damaged or corroded electrical connector at the cylinder 9 injector
  3. Chafed, broken, or shorted wire in the injector harness near the cylinder 9 injector
  4. Poor connection or corrosion at the PCM connector for the injector driver circuit
  5. Internal PCM driver circuit fault for cylinder 9 injector
  6. Aftermarket or incorrect injector installed that does not match the PCM calibration
  7. Engine wiring harness damage from heat, rodents, or previous repairs

How to diagnose and fix it

  1. Perform a visual inspection of the cylinder 9 injector connector and harness for corrosion, chafing, or loose pins
  2. Use a scan tool to command the cylinder 9 injector on and off while listening for a click, and compare with other cylinders
  3. Measure the resistance of the cylinder 9 injector coil with a multimeter and compare to the manufacturer's specification
  4. Check for voltage and ground pulses at the injector connector with a noid light or oscilloscope during cranking
  5. Inspect and test the injector driver circuit from the PCM to the injector for continuity and short to ground or power
  6. If the circuit tests good, swap the cylinder 9 injector with a known-good injector from another cylinder and see if the code follows
  7. Repair or replace the faulty injector, connector, or harness section and clear the code to verify the repair

Before you replace the cylinder 9 injector

  • A loose or corroded connector at the injector is far more common than a failed injector coil, so always inspect and clean the terminals before condemning the part.
  • The PCM may set P02F6 for a circuit that is only intermittently faulty, so a wiggle test of the harness while monitoring injector operation can reveal a problem that a static resistance check misses.
  • On engines with multiple cylinders, a misfire counter can show whether cylinder 9 is the only affected cylinder or if the fault is shared with other injectors on the same driver circuit.
  • Aftermarket injectors with incorrect resistance or spray pattern can trigger this code even when they are new, so verify part compatibility with the original equipment specification.
  • A weak battery or charging system can cause injector circuit voltage to drop below the expected range and set this code without any actual injector fault.

Can I keep driving with P02F6?

You can usually drive the vehicle short distances to a repair shop, but avoid heavy acceleration, towing, or long trips because a persistent misfire can overheat the catalytic converter and cause expensive damage. If the check engine light is flashing, stop driving and have the vehicle towed.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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