2005 ML 350: ABS, BAS, ETS/ESP Warning Lights - Control Unit Faulty?
 

2005 ML 350 (163.157), with 112K miles, presents with ABS, BAS and ETS/ESP illuminated warning lights in IC.

SDS quick test reveals a fault code for the left front wheel speed sensor. With the vehicle in Park, the data stream for that wheel shows a rapidly fluctuating vehicle speed of between 7-12 MPH, occasionally but briefly falling to 0 MPH. The data stream for the other wheel speed sensors show a vehicle speed of 0 MPH.

The ABS, BAS and ETS/ESP warning lights remain illuminated with the original left front wheel speed sensor disconnected; lights also remain illuminated following the installation of a new M-B wheel speed sensor.

The MY 2005 163 integrated the ABS and ETS control units into one unit on the front of the ABS pump. A quick look at the wiring diagram reveals the left front wheel speed sensor feeding directly to the control unit, which would suggest a faulty control unit. The control unit's wiring harness plug connector is intact and free of corrosion. The left front wheel speed sensor wire is intact and defect free.

And, on a possibly related note... the vehicle was involved in a frontal impact accident approx. 4 weeks ago; the front bumper clip was damaged but the ABS/ETS control unit itself was not impacted. The warning lights appeared shortly after the accident.

Just a coincidental failure of this control unit?

Or a control unit fault precipitated by the shock of impact? (The ABS pump/control unit assembly is mounted on the most forward lateral aspect of the left front frame rail, to the left of the radiator.)

Thanks.

What code was read from that computerl like C1 ???.

Also is the wheel bearing OK on that side?

Battery been dead or disconnected lately?