Car Scanner Pro is a powerful tool for vehicle diagnostics, offering insights into your car’s performance and health beyond standard OBD2 readers. One of its most potent features is the ability to add custom sensors, also known as custom PIDs (Parameter IDs). This functionality is particularly valuable for monitoring specific data points not readily available, such as those related to your engine’s intricate workings, including knock sensor readings. By understanding how to create and utilize custom sensors, you can significantly enhance your diagnostic capabilities and gain a deeper understanding of your vehicle’s condition. This guide will walk you through the process of creating custom sensors in Car Scanner Pro, empowering you to monitor parameters like knock sensor activity and much more.
Understanding Custom Sensors in Car Scanner Pro
Custom sensors in Car Scanner Pro allow you to retrieve data defined by your car’s manufacturer that might not be part of the standard OBD2 parameters. Think of it as creating a direct line of communication with your car’s Engine Control Unit (ECU) to request and interpret very specific information. This is achieved by sending specific commands and then decoding the ECU’s response using formulas you define. For enthusiasts and professionals alike, this opens up a world of possibilities for detailed diagnostics and performance monitoring, including the ability to track sensitive indicators like knock sensor signals which are crucial for engine health and longevity.
Key Components for Creating Custom Sensors
To create a custom sensor in Car Scanner Pro, you need to understand two essential elements: how to request the data from your car’s ECU and how to interpret the data once it’s received.
1. Command and Header: Requesting Data from Your ECU
The first step is constructing the correct request to your car’s ECU. This involves knowing the Command and, in many cases, the correct Header.
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Command: This is essentially the question you’re asking your ECU. It’s composed of a Mode and a PID (Parameter ID). For example,
010Cis a standard OBD2 command to request engine RPM. For custom sensors, you’ll need to find the specific Mode and PID codes defined by your car’s manufacturer for the data you want to access, such as knock sensor readings. This information is typically found in vehicle-specific technical documentation. -
Header: The header specifies the address where the request should be sent, particularly important for CAN (Controller Area Network) protocols. For instance,
7E0is a common header for CAN 11bit protocol. While you can sometimes leave the header blank and let Car Scanner Pro use a default functional header, many custom PIDs, especially those for more advanced parameters like knock sensor data, require a precise header to ensure the request reaches the correct module within your car’s network.
2. Formula: Decoding the ECU Response
Once Car Scanner Pro sends the command and receives a response from the ECU, you need to tell the app how to interpret this raw data. This is where the Formula comes in.
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Byte Representation: Car Scanner Pro represents the bytes in the ECU’s response with letters, starting with ‘A’ for the first byte of data, ‘B’ for the second, and so on. It’s important to note that Car Scanner Pro automatically skips header bytes, data length indicators, response markers, and the PID id itself before assigning these letters. For example, if a request for engine RPM (
010C) returns7E804410C0C9C, Car Scanner Pro would consider0Cas byte ‘A’ and9Cas byte ‘B’. -
Mathematical and Bitwise Operations: The formula field allows you to use mathematical operators (
+,-,*,/) and parentheses to define the calculation needed to convert the raw bytes into a meaningful value. For example,(A*256+B)/4is a formula to combine two bytes and then divide by four. Furthermore, Car Scanner Pro supports bitwise functions (@~,@&,@^,@<<,@>>) which are often necessary when dealing with packed data where individual bits within a byte represent different flags or values, which can be relevant for interpreting complex sensor data, potentially including some knock sensor implementations. -
Built-in Functions: Beyond basic operators, Car Scanner Pro offers a range of built-in functions to handle more complex data decoding:
GetBit(A,N): Extracts a specific bit (N) from a byte (A).SIGNED(A)/ShortSigned(A,B): Interprets bytes as signed integers.And(A,B)/Shr(A,B)/Shl(A,B): Bitwise logical and shift operations.MAX(A,B)/MIN(A,B)/abs(A): Mathematical utility functions.FLOAT32(A,B,C,D)/FLOAT64(A,B,C,D,E,F,G,H): Converts bytes to floating-point numbers according to IEEE 754 standard.if(A,B,C): Conditional logic – if A is true (1), return B, otherwise return C.SetVar(key,value)/SetVarOnce(key,value)/GetVar(key,default_value): Functions for storing and retrieving values in Car Scanner Pro’s shared memory, useful for more advanced calculations or tracking states across different sensors.PID(ID)/{name}: Allows you to reference values from other sensors within your formulas, enabling complex derived sensors.
Action PIDs
Car Scanner Pro also supports “Action PIDs.” These are custom PIDs that, when tapped, execute a command you define but do not decode any response. This is useful for triggering ECU routines, such as initiating a forced DPF regeneration or other diagnostic or maintenance procedures, depending on your vehicle’s capabilities and your knowledge of its command set. Again, proper command and header information are crucial for action PIDs to function correctly.
Naming and Configuration
When creating custom sensors, you can define the Name and Short name as you wish for easy identification within the Car Scanner Pro app. The Minimum and maximum value fields are optional and can be used to set display ranges or warning thresholds for your custom sensor.
Conclusion
Mastering custom sensors in Car Scanner Pro unlocks a new level of vehicle diagnostics and monitoring. While the initial setup requires some technical understanding of ECU communication and data interpretation, the potential benefits are immense. For those interested in monitoring parameters like knock sensor activity, or any other manufacturer-specific data, custom sensors provide the pathway to access this information directly. By leveraging the command and header settings, along with the powerful formula engine, you can tailor Car Scanner Pro to become an incredibly precise and insightful tool for understanding your car’s inner workings and ensuring its long-term health. Explore your vehicle’s technical documentation, experiment with custom PIDs, and take your car diagnostics to the next level with Car Scanner Pro.
