U1XXX - Loss Of Communication Codes
- Control module ID number provides a method for determining which control module is not communicating. Operating information and commands are communicated between control modules. When a control module has a class 2 data circuit malfunction or losses power during an ignition cycle would have a loss of communication Diagnostic Trouble Code (DTC) set by other control modules on the class 2 data circuit. Data messages are continuously exchanged between all control modules through class 2 serial data circuit. State Of Health (SOH) messages are also sent every 2 seconds to immediately detect a loss of communication between control modules. If these continuous SOH messages are not received between control modules for more than 5 seconds, a loss of communication DTC will be stored. If loss of communication (U1XXX) is set, it contains control module ID number as last 3 digits (XXX). Use this control module ID number to aide in diagnosis and to determine which control module is not communicating. See CONTROL MODULE ID NUMBERS
table.CONTROL MODULE ID NUMBERS
Class 2 Data Bus Circuit Control Module ID Number Powertrain Control Module (PCM) 016 Electronic Brake & Traction Control (EBTCM) Module 040 Sensing & Diagnostic Module (SDM) 088 Instrument Panel Cluster (IPC) Module 096 PASS-Key(R) III (PK3) Module 192