Communication Via Network

Communication via network





CAN communication
ECM (Engine Control Module) sends out and receives the following signals via the network:

Anti-lock Braking System (ABS)
Provides information so that the Engine Control Module (ECM) can determine whether any misfiring is due to road condition or to a fault in the engine management system. Also provides a vehicle speed signal, (goes via the DIM first).

Climate Control Module (CCM)
Provides information to the Engine Control Module (ECM) that A/C is selected and the request that the A/C compressor functions.

Central Electronic Module (CEM)
Is the "main computer" in the network and coordinates required information between other modules. It also controls diagnostic function by connecting the data link connector (DLC) to the network for programming and reading off diagnostic trouble codes (DTCs) and parameters.

Driver Information Module (DIM)
Provides the Engine Control Module (ECM).with information about vehicle speed.

Data Link Connector (DLC)
When reprogramming and downloading new software and fault-tracing the initiation request is transferred from VIDA via data link connector (DLC) pin 7 (also called Communication link) to the CEM which closes
2 internal relays and opens communication with the network.
The serial communication via the data link connector (DLC) (pin 7, Communication line) is only used by the authorities and certain other workshops in the USA/CDN for reading off OBD II codes using the Generic Scan Tool.

Electronic Fan Control Module
Receives a signal from the Engine Control Module (ECM) about which speed the engine cooling fan (FC) should run at.

Electronic Throttle Module (ETM)
The following signals are sent out on the network from the electronic throttle module and taken up by the engine control module (ECM):
- Provides information about current throttle position.
- Request to DIM via ECM to light ETS lamp
- Faults discovered in the Electronic Throttle Module (ETM) are stored as diagnostic trouble codes (DTCs) in the Engine Control Module (ECM)

Steering Wheel Module (SWM)
Provides information to the Engine Control Module (ECM) that the cruise control is selected and that the driver requests a change in the cruise control speed.

Transmission Control Module (TCM)
The following signals are sent out on the network from the engine control module (ECM) and taken up by the TCM:
- Engine load
- Throttle opening
- Acknowledgement of torque limiting
The following signals are sent out on the network from the Transmission Control Module (TCM) and taken up by the ECM:
- Torque limiting request stage I and II
- Request to operate the malfunction indicator lamp (MIL)
- Constant idle speed compensation (P/N position) signal