Engine Control Module: Testing and Inspection

Downloading software and replacing the control module

New software can be downloaded into the engine control module (ECM). When ordering software, the hardware and the software in the car is compared to the information in the Volvo central database. If the comparison is OK the software is downloaded to the control module. If the comparison between the car and Volvo central database is not OK, the database is updated with the car configuration. When this is complete the software is downloaded.
For more information about downloading, see Design and Function, Downloading Software.
The engine control module (ECM) is located in the cold zone in front of the windshield.
The engine control module (ECM) contains a unique code for each car for the immobilizer. The central electronic module (CEM) checks this code at engine start up. The engine will not start if the central electronic module (CEM) detects an incorrect code for the immobilizer. This means that the engine control module (ECM) cannot be switched from vehicle to vehicle.
The engine control module (ECM) must first be "unlocked" using a unique PIN for each car before it can be programmed with a code for the immobilizer. When the PIN has been approved by the engine control module (ECM), the code for the immobilizer can be programmed.
The PIN and the code for the immobilizer are obtained from the Volvo central database and sent out with the software package when software for downloading has been ordered.
All new engine control modules (ECM) have the same PIN which is preprogrammed by the control module supplier. When the engine control module (ECM) has been programmed successfully the original PIN for the car will be programmed in the engine control module (ECM) memory and will replace the preprogrammed PIN code.