Central Electronic Module Failure

What NHTSA is examining

Volvo acknowledged a problem affecting some subject vehicles involving water seepage into the plenum box area in the engine compartment.When this occurs water may enter into the interior / passenger compartment and track along the wiring harness for the Central Electronic Module (CEM), the device that controls many of the vehicle's electrical functions including wiper operation, lighting, and transmission operation.If the water reaches the CEM connector electrical faults may result.In response to such faults the CEM, a microprocessor controlled device, will attempt to reset by temporarily shutting down (for 100 milliseconds, or 0.1 seconds) and restarting; this effects various CEM functions including the instrument panel (IP) display, gauges, wipers and also the transmission gear (if it is in the overdrive range).During the reset owners may experience temporarily loss of the IP displays and an abnormal 'jerking' in the transmission/drivetrain.If the problem persist for 6 consecutive restart attempts, the CEM will enter a 'Limp Home' mode that disables non-essential electrical functions yet maintain safety critical functions such as low-beam headlights, low-speed wiper operation, brake lights, and non-overdrive transmission operation.Warning and error messages will also be illuminated in the IP display.Consumers reported experiencing conditions consistent with CEM resetting and the limp mode operation in their reports to both ODI and Volvo.No reports or allegations of crash…

Vehicles under investigation