DTC P1626: Lost Class II Communication With BCM: Description

The Class II serial data circuit is used to communicate information between PCM and Electronic Brake/Traction Control Module (EBTCM) if equipped with ABS, instrument panel cluster, PCM, Sensing and Diagnostic Module (SDM), and DLC. Each module has specific data information processed from various sensors that is sent out to Class II link in order for other controllers to utilize the information. Each controller has stored in memory specific information needed from other controllers. Each time ignition is turned on, all modules on the Class II link must first learn where the information they need comes from. Once each module receives information it needs, a source identifier attached to message will be used as identification.

Once module learns where these messages came from, it will store the specific controller ID for those information for the entire ignition cycle. If message is then lost during the same ignition cycle, a specific "U" type DTC will set. If a module never received the initial needed message, it will set DTC U1000.