The owners of certain 2020 Mercedes Benz GLC350E 4Matic SUVs could experience a loss of drive power due to a problem affecting the wiring harness going to the transmission in their vehicles.

In September 2020, Mercedes Benz first became aware of the problem after receiving a customer complaint regarding the loss of drive power in their vehicle. As similar complaints regarding GLC-Class vehicles increased Mercedes began an investigation into the problem. A production quality survey was initiated to double check the wiring harness installation in two plants producing the LC-Class. Mercedes investigated possible commonalities between the reported failures of two different platforms that are manufactured at three different plants. Mercedes also asked the wiring harness supplier to analyze any possible cause involving the wiring harness.

The investigation identified the root cause of the problem as an error in the installation of the wiring harness. Mercedes studied the potential effect of the transmission wiring harness production deviation on vehicle safety and identified the potentially affected vehicles. On July 1st 2022, they determined that there was a potential safety risk and decided to conduct a recall of all the potentially affected vehicles.

According to the defect report, the routing of the transmission wiring harness in certain 2020 GLC-Class (253 platforms) 4-Matic vehicles may not meet current production specifications. Due to deviations in the wiring harness length and the assembly process, the harness could come in contact with the front drive shaft and damage it over time. If this happens, drivers could experience a loss of propulsion and an increased risk of an accident. If the failure occurs, the driver would be made aware through a warning message in the instrument cluster.

Owners receiving notices will be asked to return to their dealers to have the transmission wiring harness inspected and replaced as necessary. The NHTSA campaign number for this recall is 22V-494.