P0201: Injector Circuit/Open - Cylinder 1

Quick Answer

• What it means: The Powertrain Control Module (PCM) has detected an electrical fault in the fuel injector circuit for cylinder 1.
• Severity: Get towed or repair immediately; prolonged driving can cause severe engine damage.
• Most common cause: A faulty fuel injector or an open/short in the injector wiring.

What the P0201 code means

The P0201 code stands for "Injector Circuit/Open - Cylinder 1." This indicates that the engine's computer, or Powertrain Control Module (PCM), has detected an electrical malfunction within the fuel injector circuit for cylinder number 1. Essentially, the PCM is not seeing the expected electrical signal from or to the injector, suggesting either a break in the wiring, a short circuit, or an internal fault within the injector itself.

In plain English, your engine isn't delivering fuel to cylinder 1 correctly because of an electrical problem with that specific fuel injector. This can lead to a misfire, rough running, and potentially significant engine damage if not addressed.

Common symptoms

• Check Engine Light illuminated
• Engine misfire or rough idle
• Reduced engine power and acceleration
• Poor fuel economy
• Engine hesitates or stumbles under load
• Raw fuel smell from the exhaust (due to unburned fuel entering the exhaust system if the injector is stuck open or leaking)
• Difficulty starting the engine

Common causes

1. Faulty Fuel Injector (Cylinder 1): The injector itself can fail internally, either electrically (open circuit, short circuit) or mechanically (clogged, stuck open/closed).
2. Open or Short in Injector Wiring: The wiring harness leading to the cylinder 1 fuel injector can become damaged, leading to an open circuit (break in the wire) or a short circuit (wire touching another wire or ground).
3. Corroded or Loose Connector: The electrical connector at the fuel injector can become corroded or loose, interrupting the electrical signal.
4. Faulty Powertrain Control Module (PCM): While less common, an internal fault within the PCM itself can cause an incorrect signal to the injector. This is usually diagnosed after all other possibilities have been ruled out.

How a technician diagnoses it

1. Verify the Code and Freeze Frame Data: The technician will start by connecting an OBD-II scan tool to confirm the P0201 code and check for any other related codes. Freeze frame data will be reviewed to see engine conditions (RPM, engine load, temperature, etc.) at the time the code was set.
2. Visual Inspection: A thorough visual inspection of the cylinder 1 fuel injector wiring harness and connector will be performed, looking for any signs of damage, fraying, corrosion, or looseness.
3. Listen to the Injector: Using a mechanic's stethoscope or a long screwdriver, the technician will listen for the clicking sound of the cylinder 1 injector to confirm it