— Mercedes-Benz CLS 450 and CLS 450 4Matics are recalled because of electrical and coolant pump problems.
More than 3,250 model year 2019 CLS 450 models are equipped with 6-cylinder gasoline engines and electrical lines that supply power to the engine coolant pumps that may contact the engine fans and chafe.
This may cause the coolant pumps to malfunction or cause a deactivation of the 48V onboard electrical systems.
The coolant temperature could increase and cause a stalled engine if the pump malfunctions, and the electrical problems can make it impossible to restart the engine if the engine is switched off by the ECO start/stop function or the “Glide” mode functionality.
Mercedes says the electric lines for the coolant pumps weren't routed correctly and could be damaged by making contact with the engine fans.
Mercedes received a report in November 2018 about a malfunctioning electric power supply to the engine coolant pump due to chafing on the engine fan, but the automaker believed it was just an isolated event.
Engineers did open an investigation but found no problems related to routing of the wiring harnesses, but in January 2019 Mercedes added clips on the harnesses. However, another complaint came in about a vehicle that didn't have the additional clip and the symptoms were the same as the first report.
Investigators determined damaged wiring insulation caused the 48V onboard electrical system to deactivate, subsequently leading to an engine stall in connection with the ECO start/stop and "Glide mode" functions. The automaker also says it cannot rule out a risk of fire due to a short-circuit.
Drivers may see warning messages concerning coolant temperatures or messages indicating electrical problems.
The recall is expected to begin October 15, 2019. Mercedes-Benz dealers will inspect the coolant pump electrical lines for damage and repair them if needed.
Mercedes CLS-Class owners may call 800-367-6372.