P0201 OBD-II Trouble Code: Injector Circuit Malfunction - Cylinder 1

Check Engine Light

P0201 code definition

P0201 is referencing a generic issue in the injector circuit in cylinder 1.

  • Note: This code is similar to P0200, P0202, P0203, P0204, P0205, P0206, P0207, P0208. In addition, this code may be seen with engine misfire, rich, and lean conditions.

What the P0201 code means

The diagnostic trouble code P0201 tells us the ECM has detected a malfunction with the cylinder 1 injector circuit. This code indicates out-of-range performance was detected in the operation of cylinder 1 injector circuit.

Once a malfunction is detected, a Check Engine Light is triggered and failsafe mode is enabled. Failsafe mode will remain in effect until normal operation is detected or the code is repaired.

What causes the P0201 code?

  • Faulty cylinder 1 injector
  • Wiring harness that has an open or short
  • Poor electrical connection in the harness or connector
  • ECM that is failing or has failed

What are the symptoms of the P0201 code?

Symptoms may be felt before a Check Engine Light is set on the dashboard. Vehicles may experience a rich or lean condition accompanied by an engine misfire. Additionally, the vehicle may run poorly or not at all. In cases where the vehicle dies, it may not restart. The vehicle may exhibit poor acceleration, lack of power, and poor gas milage.

How does a mechanic diagnose the P0201 code?

Qualified technicians will begin by hooking up an advanced scanner to the DLC port and checking for codes. Any code present will generally have freeze frame data associated with it. This tells them under what conditions, such as vehicle speed, operating temperature, and engine load, the code occurred under.

The codes will then be cleared and the test driven to see if the code will come back or if it was a one-time occurrence. If the code comes back, a visual inspection will be performed on the injector circuit and fuel injector itself.

Next, the technician will check for voltage at the injector to confirm proper operation. A scan tool will be used to monitor injector operation and a noid light will be installed in the injector wiring to test for the correct pulses of the fuel injector.

If all of this checks out, a manufacture specific ECM test will be performed.

Common mistakes when diagnosing the P0201 code

Mistakes can be made performing diagnosis of any code if proper steps are not followed or are skipped.

Though the most common cause of P0201 is the cylinder 1 fuel injector, it must be properly tested to ensure it is at fault. If the inspection is not done properly, unnecessary repairs may be done, which can waste both time and money.

How serious is the P0201 code?

The seriousness of this code can range from just the Check Engine Light being present, to the vehicle running poorly and having a lack of power. Any code that has the potential for the vehicle to die while running should be repaired as soon as possible for safe operation of the vehicle.

What repairs can fix the P0201 code?

Additional comments for consideration regarding the P0201 code

Cylinder 1 is generally found on the driver's side of the engine bay. The fuel injector will be found attached to the fuel rail installed onto the engine intake.

Fuel injectors are a common failure in vehicles with over 100,000 miles due to the contaminated particles in the gasoline. In some cases, the fuel system may be helped by using a product such as Seafoam to clean the system. This may help with injector issues in some cases.

Advanced diagnostic tools are needed to diagnose P0201 effectively. An advanced scan will be needed to check ECM recorded voltage and resistance of the injectors. This can also tell technicians how the voltage and resistance changes over time by plotting this data on a graph.

A noid light set is used to check the pulse operation of the fuel injectors. This is a more advanced test than just checking for voltage, but the ECM looks for the proper pulses to determine if the injector is operating properly.

Need help with a P0201 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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