Description
What is Nitro M-F OBD?
Nitro M-F OBD (labeled NitroLogger on the device) is a CAN bus logger and analyzer that plugs inline into the vehicle's OBD-II line with male and female OBD-II connectors, listens to two independent CAN bus channels at the same time and carries the traffic to a PC over USB.
On the PC side it works with SavvyCAN over the GVRET protocol: live CAN monitoring, ID filtering, log recording and export are done in that software. Because it listens without interrupting the line, it can be used together with an OBD tester or scan tool plugged into the vehicle.
At a Glance
| What it does | Listens to, records and analyzes CAN traffic on the OBD-II line |
| Connection | Male + female OBD-II connector, inline (on the bus) |
| CAN channels | 2 independent channels, monitored simultaneously |
| PC connection | USB (COM port on Windows) |
| Software | SavvyCAN, GVRET protocol (serial, 1,000,000 baud) |
| Typical CAN speed | 500 kbit/s (adjustable per bus in SavvyCAN) |
Key Features
What Is It Used For?
- Inspecting ECU / gateway behavior: recording CAN messages as logs and analyzing them later with filters and graphs
- Verifying aftermarket equipment: checking the effect of installed equipment on CAN traffic through recordings
- Protocol and timing studies: watching both buses at once with ID, data and timing information
- Sharing logs within a team: exporting recorded sessions and passing them on
- Test frame sending: sending CAN frames from the PC (authorized environment, deliberate use only)
SavvyCAN Connection
Connect the device to your computer over USB (it appears as a COM port on Windows) and follow these steps in SavvyCAN:
- Open Connection → Open Connection → Serial Bus Connection.
- Select GVRET as the device type and the relevant COM port as the port (serial speed 1,000,000 baud).
- Once connected, tick Enable Bus for Bus 0 and Bus 1 and set the CAN speed to match the vehicle (most OBD-II HS-CAN: 500000).
- Use SavvyCAN's logging / capture features to record.
Note: The COM port must not be in use by another application (serial monitor, an old SavvyCAN session).
Screenshots
Technical Specifications
| Microcontroller | ESP32 |
| CAN channels | 2 (Bus 0: MCP2517FD, Bus 1: ESP32 TWAI) |
| PC interface | USB (UART) |
| PC protocol | GVRET (binary serial) |
| Software | SavvyCAN (GVRET serial, dual bus) |
| OBD interface | Male + female OBD-II |
| Typical CAN speed | 500 kbit/s (adjustable) |
Frequently Asked Questions
What is Nitro M-F OBD?
It is a CAN bus logger and analyzer that plugs inline with male and female OBD-II connectors and carries two independent CAN channels to a PC over USB. The device is labeled NitroLogger.
Does it cut the OBD line while working?
No. It connects to the vehicle with the female OBD-II connector, and an OBD tester, scan tool or other equipment can be plugged into its male connector, so it works inline and listens without interrupting CAN traffic.
How many CAN channels does it monitor at once?
Two independent CAN channels. In SavvyCAN, Bus 0 is the external MCP2517FD and Bus 1 is the ESP32 internal TWAI (CAN0); both are monitored simultaneously.
Which software does it work with?
SavvyCAN. The device runs in GVRET (ESP32RET-compatible) serial mode; in SavvyCAN choose Connection → Open Connection → Serial Bus Connection, device type GVRET and the relevant COM port. The serial speed is 1,000,000 baud.
What is the CAN speed and can it be changed?
The default configuration is 500 kbit/s for high-speed OBD-II CAN. Speed and mode are set per bus in the SavvyCAN interface.
How is a log recorded and what can be done with it?
A session is recorded as a log with SavvyCAN's logging / capture features. Afterwards you can filter by ID, trigger, graph, compare and export; symbolic decoding is supported on DBC-defined networks.
Can it send CAN messages?
CAN frames can be sent from the PC for test purposes (SavvyCAN Frame Sender). The device is intended primarily for listening and recording; writing to CAN should only be done in an authorized environment and deliberately.
Is it compatible with every vehicle?
The device listens to CAN traffic on the OBD-II line; typical high-speed OBD-II CAN runs at 500 kbit/s. Brand and model compatibility is the user's responsibility.
Safety and Responsibility
Interfering with the CAN/OBD line can affect vehicle operation. Writing to CAN should only be done in an authorized environment and deliberately. The device is intended primarily for listening and recording; brand/model compatibility is the user's responsibility.