Engine Control Module: Testing and Inspection

Downloading software and replacing the control module

When replacing the engine control module (ECM), the hardware number on the control module is read and transmitted to the Volvo central database. The software is compiled depending on the configuration of the vehicle (for example, structure week and hardware number). The software is then transmitted to VIDA and downloading is carried out.
A vehicle identity check, a read off of the vehicles' new configuration for updating the Volvo central database and programming of codes are included in the download sequence. The procedure when updating software is identical except that the hardware number is not read but taken directly from the Volvo central database. For further information regarding downloading, see Design and Function, software download.
The engine control module (ECM) is included in the immobilizer system and a number of conditions must be met for the control module to approve a start.
Immobilizer code: During a start attempt, the central electronic module (CEM) transmits its immobilizer code and the engine control module (ECM) compares this with its own programmed code. This condition is met if the codes correspond.
Serial number: The serial number for the brake control module (BCM) is programmed into the engine control module (ECM). During a start attempt the engine control module (ECM) transmits a query to the brake control module (BCM) about which serial number it has programmed in and then compares this with the serial number programmed into the engine control module (ECM). This condition is met if the serial numbers correspond.
Both conditions must be met to allow a start. When replacing the engine control module (ECM), both the immobilizer code and serial number are programmed in automatically when downloading software.