FAQ and supplementary information

Once you have implemented all the J1939 messages specified in this section of the document, the next step is data validation. Please proceed with completing the validation scenarios listed below. These will ensure data from the vehicle is flowing correctly into MyGeotab. The scenarios must be completed with a GO9 device installed. Please work with your Geotab point of contact to ensure the GO device has the correct firmware version before executing the validation scenarios.

The validation scenarios to be completed are:

1. A minimum of 5 km (preferably 15 km) of driving. This driving should include segments with combustion engine activity if the vehicle in question is a Plug-in Hybrid Electric Vehicle (PHEV).

   • The minimum driving distance as stated above is a cumulative value, and therefore does not need to be completed in a single trip.

2. A minimum of one (1) AC charging event where:

   • The net gain in HV Battery SOC is at least 30%

   • The end SOC value must be greater than 80%

   • Not applicable if the EV only allows for DC charging.

3. A minimum of one (1) DC Fast Charging event for 15 minutes.

Upon completion, please inform your Goetab point of contact (or a member from the EV Solutions Engineering team). Geotab will internally review the data and let you know if any changes need to be made or if the test procedure needs to be repeated.

From a telematics device perspective: A GO9 device with beta or stable release firmware is required to collect and interpret J1939 EV messages on a vehicle.

From a diagnostic port perspective: A standard 9-pin or 16-pin port is required. Custom ports pinouts will require a modified harness and will delay the time to completing the full integration. J1939 data needs to be read by the GO device either on pins 6 and 14, or on pins 3 and 11.

The Firmware Product Guide contains information about firmware releases and the rollout process, LED lights, device beeps, listen only mode, odometer and seat belt logic, ignition detection logic, GPS precision, and more! It is recommended to read over this document so you better understand the functions and operation of the GO device.

The specifications for the GO9 device are found in the GO9 support document. The GO9 device follows the standard OBDII pinout.

All data collected by a GO device, regardless of whether or not it is J1939 EV data, is curve logged. The only exception to this is vehicle state of charge and signals that are "state" based such as ignition, seatbelt, etc. The curve logging algorithm decides which datapoints contain statistically significant information, and only sends those back to the database to avoid unnecessary data transmission overhead. The remaining datapoints are discarded prior to device data transmission. For more information, refer to the Geotab whitepaper on curve logging and a YouTube video of Geotab's CEO explaining curve logic.

Geotab has incorporated a tagging mechanism in the GO device to identify different EVs on standard and proprietary CAN protocols. In order to correctly tag as an EV following the J1939 EV protocol, the GO device needs to see the PGNs and SPNs in the following table broadcast on CAN.

This information will be useful during the testing phase of the J1939 EV implementation. For the GO device to log driving information (such as vehicle speed, energy consumption, etc.) the corresponding broadcast CAN traffic must indicate that the vehicle is in a "driving" state. This is done by setting the Ignition status to active, i.e. broadcasting PGN 64706, SPN 7315 = 1.

A similar concept applies to charging. The vehicle must be in a "charging" state in order for the GO device to log charging information (such as SOC, energy added, etc). Please see here for more information on how to implement vehicle charging status correctly.

The GO device firmware requires the following logic to distinguish between an AC and DC charge event:

• When vehicle is not charging, Set PGN 64706, SPN 7898 = 0

• When vehicle is charging (AC or DC), Set PGN 64706, SPN 7898 = 4

• For AC charging - Set PGN 61590, SPN 8207 = 1 (Not applicable if the EV only allows for DC charging.)

• For DC charging - Set PGN 64184, SPN 13171 = 1

The sign convention for HV battery current signal (PGN 61584, SPN 5920) for GO device compatibility follows what is specified in the J1939DA. The sign convention is as follows:

For HV battery current (PGN 61584, SPN 5920)

• HV Battery Current > 0 = Energy entering the battery

  • Positive values denote energy flow entering the HV battery

• HV Battery Current < 0 = Energy exiting the battery

  • Negative values denote energy flow exiting the HV battery

For EVSE1 AC RMS Current (PGN 64212, SPN 12866)

• EVSE1 AC RMS Current > 0 = Energy entering the battery

Although the J1939 EV signal set requires the implementation of HV battery current and voltage signals, the diagnostics for HV battery voltage and power are presented on MyGeotab. This is because the GO device measures HV battery current and voltage, calculates power, and sends data to the database for voltage and power.

The HV battery current is a variable signal by nature and requires lots of data points to accurately represent the signal with curve logging. Sending HV battery voltage and power information to the database is more data-efficient. If you would like to see HV battery current from the vehicle in MyGeotab, you can set up a custom report where HV battery current is calculated.

The SLI battery voltage parameter does not exist in the list of GO device supported PGNs and SPNs; however, the GO device voltage indicates the SLI battery voltage. To access this information, navigate to Engine & Maintenance > Engine and Device > Measurements. Then, for Diagnostics, select the Telematics device voltage parameter and click the Apply changes button to view the engine measurements.

A full list of all GO device supported J1939 SPNs can be found here.

The table below outlines the required payload for transmission gear change (PGN 61445, SPN 523).

After the first install, or after a device reset (unplug and replug), the GO device makes a J1939 VIN request shortly after ignition is turned on. VIN is a multi-frame CAN message and requires the use of a BAM (Broadcast Announcement Message). The table below demonstrates the transaction.

This pertains to PGN 57344 SPN 1856. The convention of buckled/unbuckled status in the GO device firmware and MyGeotab is opposite to the convention presented in the J1939DA.

In the J1939DA, the convention is:

• 0 = Unbuckled

• 1 = Buckled

However, in MyGeotab, the convention is:

• 1 = Unbuckled

• 0 = Buckled

• −1 = Unknown, this appears in MyGeotab at every ignition ON and ignition OFF

Therefore, when you send 0 in the message payload, it indicates an unbuckled status according to the J1939 standard, but displays as a 1 on MyGeotab. If you want to see a 0 in MyGeotab (buckled), you need to send a 1 in the message payload.