Car enthusiasts and professional mechanics alike are constantly seeking deeper insights into their vehicle’s performance and health. Modern cars are equipped with sophisticated onboard computer systems that monitor a vast array of parameters. To access this wealth of information, tools like the Car Scanner app are invaluable. But to truly leverage the power of Car Scanner, understanding and utilizing Car Scanner Pids is essential. This guide will delve into the world of PIDs, showing you how to unlock custom sensors and gain a more granular view of your car’s diagnostics.
Understanding Car Scanner PIDs: The Key to Custom Diagnostics
PIDs, or Parameter IDs, are codes used to request specific data from your vehicle’s Engine Control Unit (ECU) via the OBD-II (On-Board Diagnostics II) protocol. Think of them as addresses that pinpoint specific sensor readings or calculated values within your car’s computer. While Car Scanner comes with a wide range of predefined PIDs covering common parameters like engine RPM, coolant temperature, and speed, the real power lies in its ability to use custom PIDs.
Custom PIDs allow you to go beyond the standard readings and access manufacturer-specific data that might not be readily available. This could include anything from detailed fuel trim levels to individual cylinder misfire counts, depending on your vehicle’s make and model. By mastering custom car scanner PIDs, you can tailor your diagnostic experience to your exact needs, getting data directly from the source as defined by your car’s manufacturer.
Creating Custom PIDs in Car Scanner: Step-by-Step
Creating custom PIDs in Car Scanner involves understanding three key elements that define how the app communicates with your car and interprets the data it receives: Command, Header, and Formula.
Essential Elements for Custom PIDs
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Command (Mode + PID): This is the actual request sent to your car’s ECU. It’s composed of a Mode and a PID code. For example,
010Cis a common command to request engine RPM.01indicates the diagnostic mode (in this case, “Show current data”), and0Cis the PID for engine RPM. Knowing the correct Command is the first step to retrieving your desired data. -
Header: The Header specifies the address where the request is sent. For vehicles using CAN (Controller Area Network) protocols, this is often crucial. For instance,
7E0is a common header for engine-related requests on CAN 11-bit systems. In some cases, you can leave the header blank, and Car Scanner will use a default functional header for your car’s protocol. However, for most custom PIDs, especially manufacturer-specific ones, the correct header is necessary to ensure the ECU responds to your request. -
Formula (Equation): The raw data received from the ECU is often in a hexadecimal format and needs to be converted into a human-readable value. The Formula is the equation Car Scanner uses to decode this raw data. It allows you to specify how the bytes in the ECU’s response should be interpreted to display the correct sensor reading.
For example, if you request engine RPM (command
010C) and the ECU responds with7E804410C**0C9C**, Car Scanner first skips the header and protocol information (7E804410C). The remaining data0C9Cis what your formula will work with. In this case,0Cis the first byte (represented by A in the formula), and9Cis the second byte (represented by B). A typical formula for RPM might be(A*256+B)/4. This formula takes the two hexadecimal bytes, converts them to decimal, performs a calculation, and presents the engine RPM in revolutions per minute.
Decoding Data with Formulas: Advanced Techniques
Car Scanner’s formula editor is powerful, allowing for complex calculations and data manipulation. Here are some advanced techniques you can utilize in your formulas:
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Byte Referencing: You can refer to individual bytes in the ECU response using letters A, B, C, D… Z, AA, AB, … AZ, BA, BB, … BZ, and so on. A represents the first byte of data after the header and protocol bytes are removed, B the second, and so forth. Remember that formula syntax is case-sensitive.
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Mathematical Operators: Standard mathematical operators like addition (+), subtraction (–), multiplication (***), and division (/) are supported. You can use parentheses ()* to control the order of operations, for example: `(A256+B)/4
. Floating-point numbers can be used in formulas, likeA+13.54`. -
Bitwise Functions: For working with binary data, Car Scanner provides bitwise functions:
- Bitwise unary complement: @~ (e.g.,
@~A) - Bitwise AND: @& (e.g.,
A@&B) - Bitwise exclusive OR: @^ (e.g.,
A@^B) - Shift left: @<< (e.g.,
A@<<2) - Shift right: @>> (e.g.,
A@>>3)
- Bitwise unary complement: @~ (e.g.,
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Additional Functions: Car Scanner offers a range of built-in functions to enhance your formulas:
- GetBit(A,N): Extracts a specific bit (N, from 0 to 7) from byte A.
- SIGNED(A), signed(A), Signed(A): Interprets byte A as a signed 8-bit integer (-128 to 127).
- ShortSigned(A,B): Interprets two bytes (A and B) as a signed 16-bit integer.
- And(A,B), Shr(A,B), Shl(A,B): Aliases for bitwise AND, shift right, and shift left respectively.
- MAX(A,B), MIN(A,B), abs(A): Return the maximum, minimum, and absolute value respectively.
- FLOAT32(A,B,C,D), float32(A,B,C,D): Converts four bytes into a 32-bit IEEE 754 floating-point number.
- FLOAT64(A,B,C,D,E,F,G,H), float64(A,B,C,D,E,F,G,H): Converts eight bytes into a 64-bit IEEE 754 floating-point number.
- if(A,B,C): A conditional function. If A is true (non-zero), it returns B; otherwise, it returns C. Comparisons like
if(A>5;5;A)are possible. - SetVar(key,value), SetVarOnce(key,value), GetVar(key,default_value): Functions for storing and retrieving values in Car Scanner’s shared key-value dictionary, allowing data to be shared between different PIDs.
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Referencing Other Sensors: You can even incorporate data from other sensors directly into your custom PID formulas:
- PID(ID) or pid(ID): Retrieves the value of another sensor using its numerical ID (found in Settings -> Sensors). Example:
PID(5). - {name}: Retrieves the value of another sensor using its full name (case-sensitive). Example:
{Fuel temperature}.
- PID(ID) or pid(ID): Retrieves the value of another sensor using its numerical ID (found in Settings -> Sensors). Example:
Advanced PID Options: Diagnostic Commands and Action PIDs
Beyond the basic Command, Header, and Formula, Car Scanner allows for more advanced customization:
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Start and Stop Diagnostic Commands: You can add ELM327 commands to be executed before and after requesting your custom PID. These commands, separated by semicolons, commas, or backslashes, can be used for tasks like changing ECU addressing or initiating specific diagnostic sessions. Example:
ATCRA7E8,ATFCSH7E0,ATFCSD300000. -
Action PIDs: These are special PIDs that execute a command when you tap on them within the Car Scanner app. Unlike regular PIDs, Action PIDs do not decode a response. They are useful for triggering diagnostic routines, such as initiating a forced DPF (Diesel Particulate Filter) regeneration. Creating Action PIDs requires knowing the specific header and command for the desired function.
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Name, Short name, Minimum, and Maximum Fields: These fields allow you to personalize your custom PIDs within the Car Scanner interface. Name and Short name are for identification. Minimum and Maximum fields are optional and can be used to set display limits for the sensor readings.
Conclusion: Unlock the Full Potential of Car Scanner with Custom PIDs
Mastering car scanner PIDs opens up a new dimension of vehicle diagnostics. By understanding the Command, Header, and Formula, and leveraging Car Scanner’s advanced features, you can access a wealth of manufacturer-specific data and tailor your diagnostic experience to your precise needs. Whether you’re a seasoned mechanic or an enthusiastic car owner, custom PIDs empower you to delve deeper into your vehicle’s inner workings and gain a more comprehensive understanding of its health and performance. Start exploring custom PIDs today and unlock the hidden data within your car!
