Test Notes

Normal Operation
The air bag Electronic Crash Sensor (ECS) module monitors the Remote Emergency Satellite Cellular Unit (RESCU) Circuit 629 (BR) for short to battery conditions. If the ECS detects a short to battery on Circuit 629 (BR), it will store a Diagnostic Trouble Code (DTC) B1890 in memory and flash a Lamp Fault Code (LFC) 27 (or higher priority code if one exists) on the air bag indicator. The ECS module must be configured through the New Generation Star (NGS) Tester to work with the RESCU module.

Possible Causes
^ A short to battery on Circuit 629 (BR).
^ A damaged or inoperative RESCU module
^ A damaged or inoperative ECS module.
^ An ECS module that has not been configured for RESCU.