Common Vehicle Error Codes

Why is my check engine light on

Most Common Vehicle Error Codes

You may have found yourself behind the wheel of a car with its check-engine light on, and if not, it’s only a matter of time before it comes up. Don’t be alarmed, the check engine light can be triggered by hundreds of issues. Some of the issues that trigger the check engine light can be very serious, and your car may need immediate attention. To be safe, take your vehicle to a factory-trained technician at a Bob Moore Auto Group Service Department, and we can check your vehicle for error codes. Your car has a self-checking system that can locate issues and give you a specific code to identify the problem.

Vehicle Error Codes

The self-diagnostic system in your car that identifies issues and relays an error code is called the On Board Diagnostics (OBD-II). This system was invented as a result of the strict emission standards from California in the 1960s. When your check engine light comes on, it means that the OBD-II system has triggered an error code, meaning something is not right in the vehicle.

These error codes are divided into four categories identified by the first letter in the code.

  • (P) Powertrain: Issue related to the vehicle’s powertrain, including the engine, transmission, and drivetrain.
  • (B) Body: Issue related to the body of the vehicle, usually, inside the passenger compartment that involves assistance, comfort, and safety.
  • (U) Network: The computer has lost communication with another component of the vehicle.
  • (C) Chassis: Issue is outside the passenger compartment, typically including brakes, suspension, and steering.

The digit after the first letter also categorizes the codes. If the digit after the first letter is a 0, that means the code is a generic problem adopted by all car makes and models. If it’s a 1, then that means the code is unique to a specific make and model.

Most Common Error Codes

Our factory-trained auto technicians are diagnosing OBD codes every day, and some codes are more common than others. If your check engine light is on, you could be triggering one of these common error codes.

  • P0300-P0308: These codes indicate a misfire within the engine. P0300 indicates a random misfire, P0301 indicates a misfire on cylinder 1, P0302 is a misfire on cylinder 2, all the way up to P0308 indicating a misfire on cylinder 8. Misfires can happen for a multitude of reasons including spark plug failure, ignition coil failure, bad fuel injector, or low engine compression.
  • P0128: This code indicates a fault of the Coolant Thermostat, meaning that the engine coolant isn’t getting hot enough or reaching operating temperature in time. The most common cause of this code is the Coolant Thermostat is stuck in the open position.
  • P0420: This code indicates a problem within the exhaust system, usually directed at the catalytic converter. The purpose of the catalytic converter is to filter the exhaust, but if it’s getting clogged, the code can trigger.

Error codes can vary slightly according to the make and model of your vehicle, but some of the most common causes of error codes are:

  • Fuel Evaporative System Leaks
  • Wheel Speed Variation
  • Low Voltage Codes
  • Engine Misfire Codes
  • Transmission Shift Quality

If your check engine light is on, bring your vehicle to a Bob Moore Auto Group Service Department in the Oklahoma City area.