Mercedes-Benz is discontinuing the twice-recalled Robert Bosch GmbH braking system on the E-class and CLS-class sedans next summer in a move that is a blow to automotive brake-by-wire technology.
Mercedes will drop the Sensotronic Brake Control system from the E class in June 2006 when it introduces the car's midterm face-lift. At about the same time, the E class-derived CLS also will lose the system. Both cars will have a conventional hydraulic braking system. "We can now offer all the comforts of SBC in a conventional system," said a Mercedes insider. "SBC was a very expensive system."
But the source also acknowledged that customers had lost confidence in the system.
The technology eliminates the mechanical link between the driver's brake pedal and the brakes, substituting an electrical link that actuates the brake calipers.
Customer complaints were linked to the failure of software for the brake system. When the system failed, the hydraulic system took over. But that resulted in a longer stopping distance and additional brake pedal effort by the driver.
"Statistically, (the Sensotronic Brake Control is) as good as our other braking systems and sometimes better," the insider said. "But we cannot get the doubts out of customers' heads."
Mercedes' SL roadster and the low-volume SLR McLaren and Maybach supercars will retain the brake system until the end of their life cycles.
It would be too costly to re-engineer those low-volume cars to accommodate a conventional system, a source said.
Sensotronic Brake Control was supposed to highlight Mercedes' technology leadership. Instead, it created a double blow to the brand's image.
In May 2004, Mercedes recalled 680,000 vehicles to fix the complex brake-by-wire system. Then, in March 2005, 1.3 million cars were recalled, partly because of further unspecified problems with the Sensotronic Brake Control system.
$173 million price tag
Bosch has no other customers for the system, which it co-developed over nine years with DaimlerChrysler AG at a cost of 147 million euros, or about $173.3 million at current exchange rates.
A Bosch spokesman acknowledged that the system has lost some of its competitive edge.
"In 2001 we were far ahead with SBC, but conventional technology has not been standing still," the spokesman said.
"With the ESP Premium (vehicle stability system), we have all SBC functions in a conventional system."
You may e-mail Jens Meiners at [email protected]