What does fault code mean?
Robert Young
Updated on April 26, 2026
DTC's, or Diagnostic Trouble Codes, are used by automobile manufacturers to diagnose problems related to the vehicle. The first number in the DTC indicates whether the code is an SAE generic code (applies to all OBD-II systems) or is specific to the vehicle manufacturer.
Accordingly, what is a fault code?
Diagnostic trouble codes (or fault codes) are codes that are stored by the on-board computer diagnostic system. These are stored in response to a problem found in the car by the system.
Also, what is a generic fault code? Codes starting with 0 as the first digit are generic or global codes. It means that they are adopted by all cars that follow the OBD2 standard. It means that these codes are unique to a specific car make or model. These fault codes will not be used generally by a majority of the manufacturers.
In respect to this, what are engine fault codes?
Diagnostic Trouble Codes, also known as engine fault codes, are five-digit codes that identify a particular problem in the car. Each individual combination of letters and numbers relates to a specific problem within the car, whether a generic issue or a manufacturer-specific error.
How do I find my engine code?
You can find the VIN in the lower corner of your windshield on the driver's side. In the series of numbers and letters, the tenth from the left denotes the model year and the eighth is the engine code.
Related Question Answers
How do I turn my check engine light off?
If it does not go off, then your engine has a problem.- 4 Ways to Turn off the "Check Engine" Light. Method.
- Drive Your Car and Let the Light Go off by Itself.
- Turn the Car on and off Three Times.
- Disconnect and Reconnect the Battery.
- Use an OBD Code Reader.
How do you clear a DTC code?
To clear the Permanent DTC using a dedicated monitor cycle, start by repairing the fault that caused the DTC in the first place. Then clear all the codes except for the permanent DTC (if it were that easy, there'd be no problems), and make sure the Permanent DTC is the only one left.What are Eobd codes?
'EOBD' explained. EOBD, (European On-Board Diagnostic), is a system for warning the vehicle driver that there is a fault which may cause the emission levels to exceed those allowed by the European directive*. It also has the ability to store fault codes and 'Freeze Frame'* Data, concerning an emission related incident.Can Autozone reset check engine light?
Yes, we can help you clear your code; it's called telling you how to fix your damn car. Like others have said, even after clearing it, the light will come back on within 30-50 miles of driving.Will check engine light reset itself?
Reset onboard diagnostic computer. If you are sure that you have fixed the problem for which reason the check engine light was lighting up, the engine light will reset itself after 10-20 successful cycles. If you have fixed the problem, but the light persists, you will need a scan tool like an OBD reader.What does Engine code p2251 mean?
A stored code P2251 means that the powertrain control module (PCM) has detected a negative current discrepancy in the upstream oxygen (O2) sensor for engine bank number one. Bank one is the engine bank that contains the number one cylinder.How do I find my GMC engine code?
How to Diagnose GMC Check Engine Light- Locate the OBD-II port under the dashboard.
- Turn on the ignition but do not start the engine.
- Allow the OBD-II scanner to turn on and press enter to connect with the vehicle.
- Select Read Codes or Read Faults depending on the scanner.
How can I check my check engine light code without a scanner?
Using an odometer Making use of the odometer is another way to retrieve the OBD2 codes. The user is required to depress the vehicle's odometer. (The “reset” and “trip” buttons must be reset as well.) Simultaneously, the ignition key of the vehicle must be turned on and off.How can I read my engine code without a reader?
Using an odometer Making use of the odometer is another way to retrieve the OBD2 codes. The user is required to depress the vehicle's odometer. (The “reset” and “trip” buttons must be reset as well.) Simultaneously, the ignition key of the vehicle must be turned on and off.What is a pending fault code?
These codes are referred to as pending or maturing codes. Pending codes are caused by intermittent faults or faults that the PCM needs to see happen in two consecutive warm-up cycles to set the code. If the fault does not reappear within 40 warm-up cycles, the code will be cleared from memory.What will a code reader tell you?
An engine code reader/scanner can help you make the drive/no drive decision and even help you fix the problem. It works by plugging into the car's computer system and displaying a “trouble code.” A scanner gives you real-time “live” information so you see the same data your car's computer is seeing.Where can I read car codes for free?
If you have a problem with your car and you don't know what it is, most auto part stores (such as AutoZone, Pep Boys and Advance Auto Parts) will provide a free diagnostic code reading. It is also called an OBD reading. OBD stands for On Board Diagnostics.What is a good code reader for cars?
The 5 Top-Rated OBD-II Scanners| Editor's Picks | Brand | Rating |
|---|---|---|
| Best Overall | ANCEL AD310 Classic Enhanced Universal OBD II Scanner | 4.5 |
| Runner Up | ANCEL AD410 Enhanced OBD II Vehicle Code Reader | 4.3 |
| Best Budget Buy | BAFX Products Bluetooth Diagnostic OBDII Reader/Scanner | 4.4 |
| Best Basic OBD2 Scanner | Autel AutoLink AL319 OBD2 Scanner | 4.4 |
Can ob2 codes?
Most Common OBD-II Codes- P0128. Coolant Thermostat (Coolant Temperature Below Thermostat. P0171. System Too Lean. P0174.
- P0300. Random/Multiple Cylinder Misfire Detected. P0401. Exhaust Gas Recirculation "A" Flow Insufficient Detected.
- P0440. Evaporative Emission System. P0442. Evaporative Emission System Leak Detected (small leak)
