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DTC codes / P02xx · Fuel and air metering (injector circuits) / P02FC

P02FCCold Start Fuel Injection Control Circuit Low

P02FC indicates that the powertrain control module (PCM) has detected an abnormally low voltage or current on the cold start fuel injection control circuit, which is responsible for delivering extra fuel during engine warm-up. The PCM monitors this circuit and sets the code when the signal falls below the expected threshold, often due to a short to ground, a faulty injector, or a wiring issue.

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
  • Rough idle or hesitation when the engine is cold
  • Extended cranking time before the engine starts in cold weather
  • Poor fuel economy during warm-up
  • Misfire or stumble on acceleration when the engine is cold
  • In rare cases, the engine may stall shortly after a cold start

Common causes, most likely first

  1. Faulty cold start fuel injector (internal short or open coil)
  2. Damaged or corroded wiring harness to the cold start injector
  3. Poor electrical connection at the cold start injector connector
  4. Short to ground in the cold start injector control circuit
  5. Failed cold start injector timer switch or relay
  6. PCM internal driver fault (less common)

How to diagnose and fix it

  1. Inspect the cold start injector connector and wiring for corrosion, damage, or loose pins
  2. Measure the resistance of the cold start injector with a multimeter and compare to specification
  3. Check for a short to ground in the control circuit between the injector and the PCM
  4. Test the cold start injector timer switch or relay for proper operation
  5. Verify power and ground signals at the injector during a cold start
  6. If all electrical checks pass, suspect the PCM and perform further diagnostics before replacement

Cold start injector circuit pitfalls

  • A cold start injector that tests good electrically can still cause this code if the PCM's driver circuit is failing intermittently.
  • Corrosion inside the injector connector is a frequent culprit that is often overlooked during visual inspection.
  • The code can be set by a short to ground that only occurs when the engine is cold, making it intermittent and hard to reproduce.
  • Some vehicles use a cold start injector only below a certain temperature, so the fault may not appear during warm-weather testing.
  • Replacing the cold start injector without checking the circuit resistance can lead to a repeat failure if the wiring is damaged.

Can I keep driving with P02FC?

You can usually drive the vehicle with this code, but cold-start performance and fuel economy may suffer. Avoid heavy acceleration or towing until the fault is repaired, and address it promptly to prevent potential catalytic converter damage from rich running.

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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