Q: Can I Look Up What Trouble Codes Mean?

When your Check Engine Light comes on or flashes on the dash for you it is indicating there is a problem in one of the vehicle systems and has set a trouble code stored in one of the modules’ memory. The next course of action you should take is to get the vehicle to a safe stopping location to see if it is safe to continue to drive or the vehicle will need to be towed to a location to get it repaired.

In order to diagnose the Check Engine Light you will need to have the diagnostic trouble codes retrieved from the engine control module (ECM). This module has control over the Check Engine Light and other modules such as the ABS module. The module will request the ECM to turn on the Check Engine Light if needed to alert the driver of a problem in the system that the module monitors.

To get the trouble codes, you would need to hook up a scanner to the OBD connector under the dash or next to the center console on most vehicles. Some vehicles have a dash display that can display codes itself without an external scanner. The scanner will need to be used on most vehicles, though.

After hooking up the scanner and turning it on, you will then have to turn on the ignition key. The scanner may give you one or more options depending on the scanner used. You may have to select the module to scan and should start with the engine first. Once selected, the scanner may ask for you to select diagnostic trouble code (DTC), live data or freeze frame. Select DTC to get codes, live data to look at a sensor reading to help diagnose a code later on, or freeze frame data to see when the last code was set.

Once you select DTC to be retrieved, the scanner will display any codes in the computer memory. The codes should be written down before moving forward with diagnostics. You should then look at the freeze frame data to see when the problem happened and the code was set in memory. This may tell you the speed, temperature, throttle position, and other information to help you in diagnostics of the code. On some cheap scanners it will only give you the code number, but on most better scanners it will give you the code and its meaning. If you have a less expensive scanner then you can do a simple search online for your diagnostic code](https://www.yourmechanic.com/advice/tag/diagnostics). If you do not find your code or need help with the code, then contact a mechanic to come and help you diagnose the DTC you are getting.

The DTC is only part of troubleshooting the code you are getting. I have seen too many misdiagnoses of a problem because someone replaced a component based on the code retrieved only and not on a diagnostic pinpoint test of the code. Have the code pinpoint test performed to isolate the failure instead of a guessing by the code only.