GM Class 2 to CAN Converter – KCP VPW-1

The KCP VPW-1 Class 2 to CAN Converter allows you to monitor and log data from the GM Class 2 network (SAE J1850 VPW) using standard CAN logging hardware and software.

GM Class 2 is a single-wire communication network operating at 10.4 kbit/s, which cannot be read directly by conventional CAN tools. The KCP VPW-1 listens to the Class 2 bus, checks the CRC of every received message and forwards valid messages over CAN using 29-bit extended identifiers derived from the original Class 2 addressing.

This makes it possible to capture and analyse GM vehicle communication using a wide range of commonly available CAN logging tools. The converter preserves the original message structure without interpreting or modifying the data.

Vehicle Compatibility

The KCP VPW-1 is designed for GM North American vehicles using the SAE J1850 VPW (Class 2) communication protocol, generally from 1996 to 2005, with some applications extending to 2007.

Compatible applications include:

• Chevrolet Corvette C5 and C6
• Chevrolet Camaro and Pontiac Firebird with LS1 engines
• GM trucks and SUVs
• Cadillac models from the applicable years
• Buick models from the applicable years

A quick way to identify the correct communication protocol is to check for the purple Class 2 wire on pin 2 of the OBD2 connector.

Not compatible with: GMLAN vehicles (generally 2007 and newer) or older vehicles using ALDL communication (pre-1996).

Compatible with Standard CAN Logging Software

Once the Class 2 messages have been converted to CAN, you can use your preferred CAN logging and analysis software. The converter is not restricted to a specific brand or software package.

Your CAN interface or logger must support:

• 500 kbit/s CAN communication
• 29-bit extended CAN identifiers

The original Class 2 addressing information is retained in the CAN identifier, allowing messages to be grouped and analysed according to their source module and message type.

Complete Kit – USB-C to CAN Adapter Included

The KCP VPW-1 is supplied with a USB-C to CAN adapter, allowing you to connect the converter directly to a laptop and start logging vehicle data.

The included adapter is based on the STM32F072 processor and uses CANable/candleLight-compatible firmware. This makes it compatible with a wide range of CAN software on Windows and Linux.

Kit contents:

• KCP VPW-1 Class 2 to CAN Converter with trace firmware
• OBD2 connection cable (J1962)
• USB-C to CAN adapter (STM32F072, CANable/candleLight compatible)

Technical Specifications

• Input protocol: GM Class 2 / SAE J1850 VPW
• Class 2 bus speed: 10.4 kbit/s
• CAN output speed: 500 kbit/s
• CAN identifiers: 29-bit extended
• CRC validation of received messages
• Receive-only operation
• USB-C connection to laptop via included CAN adapter
• Compatible with various CAN logging and analysis applications

Important Information

The KCP VPW-1 is a receive-only interface. It does not transmit messages onto the Class 2 bus and cannot be used to request diagnostic data, read or clear fault codes, or replace missing vehicle modules.

The converter does not decode vehicle data and is not supplied with a DBC file, channel database or predefined parameter descriptions. Identifying and interpreting the recorded messages is the responsibility of the user.

Messages with payloads longer than six bytes are truncated to six payload bytes. A counter on the USB status output makes this visible.

Firmware: The converter is supplied with calibrated trace firmware. Modifying or reflashing the firmware is not recommended. Reflashed boards are not covered by warranty or technical support.

PCB servicing: The 3.3V pin on the CANduino module has intentionally been removed to ensure correct operation of the receiver. This modification must remain in place. Always refer to the supplied product sheet before carrying out any work on the PCB.

Limited availability: This is a limited production run. Only four units are available, and this PCB version will not be manufactured again.

KC Performance – KCP VPW-1

Make GM Class 2 vehicle communication accessible through standard CAN logging hardware and software.

Note regarding product photos: The last three photos show an example of how we have used and installed the converter in our own application. These additional components and installation parts are for illustration purposes only and are not included in the supplied kit.

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