OPERATION

In modern networked vehicles it is becoming increasingly difficult to intervene in the on-board electrical system for modifications, or retrofitting not done by the vehicle manufacturer. The conventional hardwired 12 volt switched circuit is no longer feasible in these vehicles.

Today, switches are connected close to the fitted control module and deliver voltage-coded or bitcoded signals over network bus circuits. In control modules these signals are mostly converted into Controller Area Network (CAN) messages and transmitted on the CAN data bus circuit. A second control unit installed close to the actuator (lamp, motor, valve...) receives this signal and energizes the actuator with the operating current.

An intervention in the on-board electrical system is only possible with the Programmable Special Module (PSM). The PSM can transmit and receive messages over the vehicle CAN data bus circuit. The PSM is connected to the CAN B BUS and access to the CAN C BUS is accomplished through the gateway function of the EZS.

As a result messages containing the following can be received and sent by the PSM:

- commands (e.g. switch on rear fog lamp)
- status reports (e.g. right sliding door open)
- measurement values (e.g. outside air temperature 21° C)

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Operation

Use the Manual With the Right Hardware

When to See a Mechanic