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P0201 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


Cylinder 1 Injector Circuit Malfunction. The code P0201 refers to a problem in the injector circuit in cylinder 1.


The P0201 code indicates that the Powertrain Control Module (PCM) has detected a problem in the injector of cylinder 1 or the wiring to the injector itself. The PCM maps the injector when the injector is activated; the PCM checks to see the voltage pulled “low voltage” or close to zero voltage.  If the injector is off, the PCM checks the injector to receive a voltage close to a battery operating voltage or “high voltage.” If the PCM does not receive the voltage within the parameters, it will set the P0201 code. The PCM also monitors the resistance of the circuit, and if the resistance is very low or very high, the PCM will trip this code.


The following is a list of reasons that might cause this code to show up:     1. Faulty cylinder 1 injector     2. Poor electrical connections in the wiring harness or the connector     3. ECM that is faulty     4. Opening in the wiring harness to the injector     5. Short in the wiring harness to the injectorA faulty cylinder 1 injector is usually the cause of this code, but it does not rule out the possibility of other reasons.


These symptoms are visible before the PCM sets off a Check Engine Light.Your vehicle can run either a rich or lean mixture alongside engine misfires. Apart from this, your machine may drive very poorly or sometimes may not drive at all. In such cases where the vehicle does not run smoothly, it may sometimes not restart. Your vehicle may accelerate slowly, have a lack of power, and have very low mileage.


We suggest you take your vehicle to a qualified technician to check your vehicle thoroughly. A proper mechanic will always have an advanced scanner far more capable than an OBD scanner tool; you might have to check your vehicle for all fault codes. This advanced analysis will tell them under what conditions (like speed, engine operating temperature, load, etc.) did code occur.

As always, ensure that they clear the code, drive the vehicle for a sufficient time to make sure the code does not show up again by the PCM.

If the same P0201 code appears, make sure to check the injector circuit thoroughly and, along with that, the fuel injector itself.

After confirming that the injector is working, check the voltage at the injector to check if it is within the required range. A scan tool helps to check the injector, and a noid light is installed in the injector wiring to check the fuel injector.

Common mistakes

This fault needs careful handling, as it can be easy to misunderstand the symptoms if you are trying to fix it before the code shows up,

Although the most common and likely cause of the code is a faulty fuel injector, you must test it properly yourself or use the services of a trained mechanic to perform the check to validate if the fuel injector is functioning or faulty.

This way, you save any unnecessary bills.

Check all the wiring for any opens or shorts throughout the line.

Keep in mind that the ECM/PCM might be at fault, and this is where resetting the code and driving the car can help you understand the code and whether a faulty ECM/PCM is triggering it.

How serious is this?

This code might mean your car could stall or not start at any time, and hence it is advised to check this code and fix it as soon as you can. While driving with this code, your vehicle might run poorly and have low mileage.

What repairs can fix the code?

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Here are some possible ways of resolving issues related to this code:

  • Replacing the fuel injector in cylinder 1
  • Fixing wiring along the line
  • Replacing wiring along the line
  • Repairing or replacing the ECM/PCM

Related codes

  • P0200 Injector Circuit Malfunction
  • P0202 Injector Circuit Malfunction – Cylinder 2
  • P0203 Injector Circuit Malfunction – Cylinder 3
  • P0204 Injector Circuit Malfunction – Cylinder 4
  • P0205 Injector Circuit Malfunction – Cylinder 5
  • P0206 Injector Circuit Malfunction – Cylinder 6
  • P0207 Injector Circuit Malfunction – Cylinder 7
  • P0208 Injector Circuit Malfunction – Cylinder 8

Apart from this, the P0201 code may show up alongside engine misfire, rich, and lean running conditions.


In any vehicle with over 95,000 miles run, it is likely to have a faulty fuel injector. Check your vehicle’s user manual to find cylinder 1 and examine the fuel injector.

To get an advanced scan and thorough check, consult a qualified mechanic.

P0201 Code – What Does It Mean & How To Fix It