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▷▷ 2021 ▷ P0303 OBD II Trouble Code, Meaning and Causes Ventos.site

3 julio, 2021


If the P0303 code keeps the Check Engine Light bright, you’re probably wondering what it means. Short answer? The P0303 Diagnostic Trouble Code (DTC) indicates a misfire on a cylinder 3. The long story? We cover it in detail below.

Meaning and cause of the P0303 code

Like all DTC codes, this code also means that something is wrong with the interior body of your vehicle. When the sensors inside your car detect a fault of some kind, the OBD-II system displays a DTC. In this case, because the DTC is P0303, your OBD-II informs you that there is a misfire condition on cylinder 3. If you are wondering what a misfire is, it is simply a misfire that may be caused by a myriad of reasons, including poor fuel quality, lack of spark, low compression, etc.

Simply put, when your OBD-II system detects multiple cylinder 3 misfires, the Check Engine Light will come on and alert you that something is wrong. The light will shine until the problem is solved.

check engine light on


What causes a misfire or the P0303 code?

There can be several reasons for the P0303 code, but some of the most common include:

  • Defective spark plugs
  • Defective plug cable
  • Defective coil pack
  • Fuel injection problems
  • Incorrect fuel pressure
  • Blown exhaust valve
  • Sensors or computer problems
  • Poor fuel quality or running out of gas

Related Post: Best OBD2 Scanner

Symptoms of the P0303 code: p0303 code español

Just as there can be several reasons for the P0303 code to appear, there can also be many different symptoms. That said, some drivers will only see the Check Engine Light glow, but will not experience any other symptoms. Other drivers, on the other hand, may experience a variety of different signs that something is wrong with their vehicle. Common symptoms include:

  • Engine is harder to start
  • The vehicle may malfunction
  • Vehicle may stop, fail
  • Choppy acceleration
  • Engine may stumble
  • Poor gas mileage.

Diagnosis and repair of the P0303 code. obdii p0303

Because there can be many causes for the P0303 code, it is important to check the vehicle properly and thoroughly. To do this, you will need a good mechanic, first and foremost. This is crucial because misdiagnoses are quite common with this code. For example, ignition system components are often completely replaced by mistake. Of course, these components generally They are the culprits, however, are far from the only possible cause of the P0303 code. A misdiagnosis will cost you more money and can also lead to various driving problems.

Although this DTC can cause drivability problems, such as a malfunctioning engine, should be able to drive to safety. Once there, the vehicle can be diagnosed and repaired fairly quickly.


To diagnose DTC P0303, a mechanic will (should) do the following:

  • Assemble a DTC scan tool to check for current and pending codes (if you want to do it yourself, just get a DTC reader or scan tool, but note that scan tools are more recommended)
  • Perform an inspection and look for damaged wiring, broken components, general wear and tear, etc.
  • Repair or replace corroded, damaged, or disconnected connectors, wiring, and components
  • Restart the system after repairing what needs to be repaired. If nothing needs to be repaired, mount the scan tool or DTC reader to the connector and write down all stored codes as well as freeze frame data because this information can be helpful when diagnosing intermittent conditions.
  • Take the test drive and see if the code comes back.

After the test drive, there are two possible scenarios: the code does not return immediately, or the code is stored but there are no symptoms. In the first case, the vehicle could have an intermittent condition that is often difficult to diagnose. Sometimes it is necessary to allow the condition to get worse before it can be properly diagnosed. In the latter scenario, the mechanic will have to reset the PCM and then see if the code returns.

In either case, proper diagnosis and repair require careful inspection. It is important to follow a certain procedure …



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