Syrus 4G Safe Engine Cutoff Using ECU Speed

This functionality allows the device to evaluate vehicle speed using data coming from the CAN/ECU network, so the safe shutdown condition can still be met even when GPS speed is unavailable, such as in scenarios affected by GPS jamming.

Overview

In the standard SECO flow, safe engine cutoff depends on conditions such as low vehicle speed. In some environments, a GPS jammer can prevent the device from receiving valid GPS data which may block the normal speed-based validation.

With this implementation, SECO can use ECU-reported speed instead of GPS speed, allowing the device to execute Output 1 activation in safe mode as long as the configured ECU speed parameter meets the shutdown conditions.

This functionality was released in syrus-gps 1.10.5

What you'll need

A Syrus 4G device
syrus-gps 1.10.5 or above installed on the unit
ECU/CAN speed data available on the vehicle
Access to the device terminal
Knowledge of the correct ECU speed parameter reported by the vehicle

Install or update the required package with:

apx-core install syrus-gps

❗️
Choosing the wrong ECU parameter for speed is critical and may cause the vehicle to be turned off under unsafe conditions.
Before enabling this feature, confirm which ECU parameter on the vehicle truly represents vehicle speed.
You can inspect the available ECU parameters on the unit with:
apx-ecu list_parameters

Supported ECU speed parameters

The ECU speed configuration is restricted to a pre-defined list of valid speed-related parameters.

VALID_ECU_SPEED_LIST
  fef1_2-3,
  febf_1-2,
  fee8_3-4,
  000d_4_obd2

Use values exactly as listed and always in lowercase.

Supported Values

```
fef1_2-3
```
```
febf_1-2
```
```
fee8_3-4
```
```
000d_4_obd2
```

Enable ECU-based SECO

To enable the SECO mechanism using ECU speed, send the following command to the unit:

apx-seco set --ecu_speed=xxxx_x-x

Where xxxx_x-x is one of the supported values from the valid list.

Example

apx-seco set --ecu_speed=fef1_2-3

This configures SECO to evaluate safe shutdown conditions using ECU speed parameter fef1_2-3.

Remove ECU-based SECO configuration

To remove the ECU speed definition from SECO, send:

apx-seco remove --ecu_speed

Recommended deployment procedure

Verify package version

Confirm the unit is running a compatible syrus-gps version

Inspect ECU parameters

List the ECU parameters available on the vehicle:

apx-ecu list_parameters

Identify the correct speed source

Match the vehicle's reported speed parameter against the approved list:

fef1_2-3
febf_1-2
fee8_3-4
000d_4_obd2

Apply the configuration

Enable SECO using the validated ECU speed parameter:

apx-seco set --ecu_speed=<valid_parameter>

Example:

apx-seco set --ecu_speed=fef1_2-3

Validate behavior

Test that the device can execute Output 1 safe activation even when GPS data is not available, provided ECU speed satisfies the safe shutdown conditions.

Expected behavior

After configuration:

The SECO mechanism can use CAN/ECU speed as the speed reference
The device can continue evaluating safe shutdown conditions even without GPS speed
Output 1 can be activated in safe mode when ECU speed indicates the vehicle is within the permitted shutdown threshold

Command summary

# install or update syrus-gps
apx-core install syrus-gps

# see list of available ecu parameters
apx-ecu list_parameters

# Enable ECU speed for SECO:
apx-seco set --ecu_speed=fef1_2-3