Monitoring Molly’s Vitals
February 2, 2020

There really is no need to monitor the engine for failure, as the FUSO Engine Management System seems to alert us the moment anything is even slightly wrong. Rather we keep track of Molly’s engine and vital statistics more for fun and long term trends.

How is it all Wired Up?
The collection of cables connecting Molly to the Cradlepoint.

To make this all work we wired the OBDII port on Molly to the USB port on the Cradlepoint. This involves a series of different cables connected together to form the necessary chain of protocol conversions.

Cradlepoint OBDII connection kit.

First the OBDII port is converted into a more common, computer friendly format via the B+B Smartworx’s LD3IC-S data-interface adapter, sold by Cradlepoint. This cable has a serial RS-232 output. However, the Cradleport doesn’t understand RS-232, so another cable is required to convert the RS-232 serial format into the USB serial format. This is easy enough with a FTDI, chip-based, Serial-to-USB converter cable. And between these two protocol conversion cables we have a null modem RS-232 extension cable, which spans the distance from the front of the truck, where the OBDII port is, to the electrical cabinet in the house where the Cradlepoint is located. Finally, the Cradlepoint is connected to the computer via an ethernet cable. RS-232 is a very old and slow communication protocol, but for this application it gets the job done.

The Cradlepoint router already has the needed software to receive the engine diagnostic information and transmit it to the computer as part of the GPS tracking system.

Cradlepoint sells a serial-to-USB cable they call a COR Extensibility Cable. Unfortunately this solution did not work for us as this cable plugs into the extensibility expansion port, and that is already being used by the extensibility dock. So instead we used an FTDI serial-to-USB converter cable and plugged it into the free USB.

Vehicle Diagnostics

There is a long list of possible vehicle diagnostics information available, but not all of it is actually available. For our setup it seems that FUSO implements the following values:

0x00 Vehicle Speed
0x01 Engine Speed
0x02 Throttle Position
0x07 Engine Coolant Temp
0x08 Ignition Status
0x09 MIL Status
0x0C Fuel Rate
0x0D Battery Voltage
0x0E PTO Status
0x10 Misfire Monitor
0x11 Fuel System Monitor
0x12 Comprehensive Component Monitor
0x13 Catalyst Monitor
0x14 Heated Catalyst Monitor
0x15 Evaporative System Monitor
0x16 Secondary Air System Monitor
0x17 A/C System Refrigerant Monitor
0x18 Oxygen Sensor Monitor
0x19 Oxygen Sensor Heater Monitor
0x1A EGR System Monitor
0x1C Ambient Air Temperature
0x22 Trip Odometer
0x23 Trip Fuel Consumption
0x2C Miles per Gallon

Cradlepoint has a good guide on how to setup your router and how to enable or disable the above values. We just enabled every value, because you never know when you want to go back in time and see what the values were.

We also configured the router to send the engine diagnostics to our computer along with the GPS coordinates. This way we can see what the engine was doing relative to where Molly was geographically. For example, we can compare throttle position and engine speed with altitude.

Throttle Position is available from the OBDII port
Engine Speed (RPMs) is available from the OBDII port
Altitude is available from the GPS coordinates