¶ General Concept
In this guide, parameter identification is based on recorded CAN logs rather than live CAN bus monitoring. This approach significantly reduces the amount of time required to work with the vehicle. Once the logs have been recorded correctly, they can be analyzed repeatedly without needing access to the vehicle.
It also allows log recording to be performed by a technician with no CAN decoding experience. As long as a video recording and a description of the performed actions are available, another specialist can complete the entire decoding process.
The general workflow for identifying any CAN parameter is:
Log Recording → Analysis → Decoding → Validation
CAN parameters can be divided into three main categories:
- Discrete parameters — sensors or states that can take one of several predefined values.
Examples: Ignition (ON/OFF), Driver Seat Belt (Fastened/Unfastened), Gear Position (P/D/R/N).
- Analog (Numeric) parameters
- Dynamic — parameters that change continuously and are difficult to hold at a fixed value.
Examples: Engine RPM (typically 700–800 RPM at idle), Vehicle Speed (difficult to maintain at one exact value, especially at low speeds). - Static — parameters that can remain constant for an extended period.
Examples: Fuel Level, Odometer, Engine Hours.
- Dynamic — parameters that change continuously and are difficult to hold at a fixed value.
Although the overall workflow is the same for all parameter types, the analysis techniques differ because each type behaves differently and requires a different approach to identifying changes.
It is recommended to study the chapters in sequence. Some concepts are explained only once and are not repeated in later sections.
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Finding Discrete Parameters