Modern auto electrics require a deep understanding of digital protocols, especially when installing telematics systems. CAN-Log (Controller Area Network Logging) is a technology that allows trackers to read data directly from the vehicle's on-board network, minimizing interference with wiring. Unlike analogue sensors, the digital approach provides highly accurate readings of fuel consumption, battery charge level and mileage.
Series devices fairway (Farvater) have proven themselves as reliable solutions for monitoring special equipment and commercial vehicles. However, correct operation of the system is impossible without correct pinouts and software filter settings. Errors at this stage can lead to a “storm” of messages on the bus or incorrect display of data on the monitoring server.
In this article we will examine in detail the physical aspects of the connection and logical settings. The key point is to correctly determine the Baud Rate of the tire of a particular vehicle, since a mismatch in speeds will make data exchange impossible. You will learn how to safely connect equipment and configure it to operate in difficult operating conditions.
Operating principles of the CAN bus in telematics
Protocol CAN was designed to allow different electronic control units (ECUs) to communicate over a two-wire line. In the context of GPS monitoring, the tracker acts as a passive observer or, less commonly, an active participant in the network. It reads the “frames” that are sent, for example, by the engine control unit or the tachograph.
Main advantage of using CAN-Log before connecting analog sensors is versatility. You don't have to dig into the fuel tank or find the tachometer wire. All the necessary information already circulates via twisted pair cables inside the cabin or frame of the car. Tracker fairway it simply “listens” to this stream and allocates the necessary identifiers.
⚠️ Attention: Direct connection to the CAN bus without galvanic isolation or buffering can lead to failure of not only the tracker, but also expensive vehicle control units. Use only certified CAN adapters.
There are several physical levels of bus implementation, and it is important not to confuse them during installation. Most often used in passenger cars and trucks High-Speed CAN, operating at a speed of 500 kbit/s. However, in passenger cars it is often found Low-Speed CAN (125 kbit/s) or Single-Wire CAN, requiring specific approaches to connection.
Physical pinout of Fairway connectors
Line devices fairway usually equipped with specialized connectors for connecting to the CAN bus. The standard pinout includes power, ground and data line contacts. To ensure stable communication, it is critical to maintain the polarity of the wires CAN-High and CAN-Low.
In a standard 4-pin tracker connector, the pin distribution often looks like this: the red wire is responsible for power (+12/24V), the black wire is for ground (GND), the yellow wire is for the CAN-H line, and the green wire is for the CAN-L line. However, before connecting, always check the technical documentation for the specific modification of your device, as color markings may vary.
Table of color markings for different revisions
In older revisions of Fairway trackers, the CAN-H line could be indicated in white, and the CAN-L line in gray. In new models, yellow and green colors have become standard, respectively. Always check the sticker on the device body.
To connect to the vehicle's on-board network, you need to find a diagnostic connector OBD-II or lead the wires directly to the comfort unit or engine. In the OBD-II connector, the CAN pins are usually located on pins 6 and 14 (for High-Speed) or 1 and 9 (for Low-Speed). The use of high-quality connectors and heat shrink will protect the connection from oxidation and vibration.
Configuring CAN filtering parameters
After the physical connection, the software configuration stage begins. The tracker must know which messages it needs to record and transmit to the server. For this purpose a mechanism is used CAN filters. Without filtering, the device will be overloaded with thousands of unnecessary messages, resulting in buffer overflow and loss of important data.
Configuration is done through the configuration utility provided by the manufacturer. You need to select the make and model of the car from the list or download a ready-made CAN profile. The profile contains message IDs (for example, 0x18FEF100 for J1939) and bytes containing the necessary information: fuel level, engine speed, gas pedal position.
- 🔹 Bus speed detection: select 250, 500 or 1000 kbps depending on the vehicle protocol.
- 🔹 Masks and filters: configure message IDs that the tracker should broadcast.
- 🔹 Conversion factors: specify multipliers for converting raw data (Raw Data) into understandable quantities (liters, percentages).
Pay special attention data scaling. The value received over the bus is often just a number from 0 to 255 or 0 to 65535. To obtain the actual fuel level in liters, it is necessary to apply a linear conversion formula, the coefficients of which are taken from the car manual or calculated experimentally.
Protocol compatibility table
Different classes of vehicles use different data exchange standards. Understanding these differences helps you quickly find the desired profile in the tracker settings fairway. Below is a summary table of the main protocols supported by modern CAN adapters.
| Protocol | Scope of application | Speed (kbit/s) | Connector type |
|---|---|---|---|
| J1939 | Trucks, special equipment, buses | 250 | 9-pin / OBD-II |
| KWP2000 | Passenger cars (old standards) | 5-10 | OBD-II |
| ISO 15765-4 | Modern passenger cars (CAN) | 500 | OBD-II |
| Modbus | Industrial equipment, refrigerators | 9.6 - 115.2 | RS-485 |
When working with special equipment (excavators, loaders) the J1939 protocol is often found. It is characterized by a higher load capacity and a specific structure of PGN (Parameter Group Number) messages. Fairway trackers do an excellent job of decoding this data, allowing you to monitor the operation of hydraulics and attachments.
Diagnosing and eliminating connection errors
Even with the correct pinout, situations may arise when data does not reach the server. The first sign of a problem is that there are no values in the Flow or RPM fields when the engine is running. In this case, error messages often appear in the device logs. CAN Bus Off or queue overflow.
One common reason is the lack of terminal resistors in the circuit. The CAN bus requires two 120 Ohm termination resistors at the ends of the line. If the tracker is connected in the middle of the circuit, there are usually no problems, but when connected at the end of a long line, it may be necessary to install an additional resistor.
⚠️ Attention: If after connecting the tracker the car stops starting or the “Check Engine” light comes on on the instrument panel, immediately disconnect the device. There is probably a short circuit in the CAN lines or a network interruption.
For diagnostics, use an oscilloscope or CAN analyzer. Once connected to the line, you will be able to see the “live” signal. The presence of clear rectangular pulses without strong distortion and “ringing” indicates good physical contact. If there is no signal, check the integrity of the wires and the quality of the twists.
Installation and testing instructions
Tracker installation process fairway using a CAN bus requires care and consistency of actions. Violation of the order of operations may lead to the need to reconfigure the entire device or even reflash it. Follow the step-by-step algorithm for guaranteed results.
☑️ Checklist for installing a CAN tracker
Start by finding the diagnostic connector. If the connection goes through it, use a ready-made adapter cable. If insertion into wiring harnesses is required, use the method of “piercing” the insulation only in extreme cases; it is preferable to strip the contacts and solder them with subsequent insulation. This will ensure reliable contact for years.
Once physically connected, turn on the car's ignition. The status indicator on the tracker body should start blinking at a certain frequency, indicating registration in the GPRS/GSM network. At the same time, the indicator should light up or flash CAN status, indicating bus activity.
Use a multimeter to check the voltage on the CAN lines. At rest (recessive) the voltage on both wires should be about 2.5V. When transmitting data (dominant) to CAN-H it rises to 3.5V, and to CAN-L it drops to 1.5V.
Frequently asked questions (FAQ)
Is it possible to connect the Fairway to the CAN bus without an additional adapter?
Many modern models of Fairway trackers already have a built-in CAN module and connect directly to the CAN-H/CAN-L wires. However, some older models or specific protocols (for example, J1939 at 24V) may require an external CAN adapter or level converter.
Why does the tracker show fuel consumption but not mileage?
Most likely, the message containing odometer data was not selected in the filter configuration, or the byte responsible for this parameter was incorrectly specified. Check the CAN profile settings and make sure the odometer message ID matches the ID in your vehicle.
Does connecting a CAN logger affect the vehicle warranty?
Since the connection is made in parallel to the existing bus without breaking the standard circuits and interfering with the operation of the ECU, the integrity of the wiring is not formally compromised. However, dealers may regard any third-party intervention as a reason to void the electrical warranty, so it is recommended to use standard diagnostic connectors.
What to do if the vehicle tire speed is unknown?
Try going through the standard values (125, 250, 500, 1000 kbps) in the tracker settings. With the correct speed, the number of received messages (RX count) in the device statistics will increase sharply. You can also find information about speed in the technical documentation for a specific car model.
Correct configuration of CAN filters is 90% of success. Even an ideal physical connection will not work if the tracker does not know which bytes of data it needs to extract from the general flow of information.