Diagnostic Procedure

If U1088 stored as a "HISTORY" code and is the only one set, check Air Bag Module (SBM) connector power, ground and serial data terminals for poor connections. See WIRING DIAGRAMS. If multiple communication DTCs are set, perform Class 2 Data Link Connector System Check. See CLASS 2 DATA LINK CONNECTOR SYSTEM CHECK  under SYMPTOM TESTS. If DTC U1040 and U1088 are set together, they may have been set falsely by ignition switch being rotated slowly. If codes were set together, clear codes and see if they return.