OBD-II (On-Board Diagnostics II) trouble codes are alphanumeric codes used to identify potential problems with a vehicle. These codes are standardized across the automotive industry, making it easier to diagnose and repair issues. Chassis trouble codes are a specific category of OBD-II codes that begin with the letter "C" (e.g., C0xxx). These codes indicate problems with the vehicle's chassis and related systems, which generally include mechanical systems outside of the powertrain and body. Common chassis systems monitored by these codes include:
Chassis Codes (C) are the category of items that are outside of the passenger compartment and includes the mechanical systems such as brakes, steering and the suspension system. When the system detects a "problem" a code is set and the check engine light will come on. To read the code you can use either a OBD Code Reader or a OBD Scan Tool which plugs into the OBD port.
Generic chassis codes are defined in the OBD-II standards and are general codes which will be used by manufactures to discribe a common fault. Manufacture specific codes are added by the manifacturer when there is no generic code that is specific enough to discribe the issue or problem.
A inexpensive basic OBD2 code reader is a basic tool which is usually limited to just being able to read most of the stored trouble codes and being capable of clearing most of the stored trouble codes. A bi-directional scanner does so much more than a basic code reader due to it being capable of bi-directional or two way communication with ALL the vehicles various computer systems and sub systems. With a bi-directional scanner you can reset the codes and do advanced tests (turn systems on or off, etc) on all of the various systems and components which you can not do on a basic OBD-II reader.