PeachParts Mercedes-Benz Forum - W210 Dies On Freeway - Cranks

A photo of my roadside service set for Mercedes-Benz...A story of spending the night on top a mountain with your family in a W210 and no blankets:

The saga begins...

Friday night, February 14th, 2014 - our 4th wedding anniversary, 9:40pm PST, my wife calls from 50 miles away to say the W210 just shut down as she was getting on the freeway. I gas up the BMW and start heading out to the location in the middle of the Mojave Desert on a Mountaintop known as Cajon Pass, elevation 4,200 ft/asl. Along the way, I stop at an Autozone to try and get a crank angle sensor, but none are in stock, so I drive on up the hill to meet with my wife and 5 year old boy.

Upon arrival, the Benz cranks over smartly but no start. Fuel in the tank and pressure is in the rail. I check all fuses to no avail. Wife described the failure as immediate shut down without sputter or other incident. Plugging in my scan tool (Launch Diagun X-341 with both 16 pin OBD2 and 38 pin MBZ Proprietary) I am meet with "Unable To Establish Connection With Vehicle ECU" message. 12 volts was present at the data link, but no serial buss signal from ECU. Cooling fan running continuusly when key is on...a fail safe feature and indication of no-signal from ECU in this platform.

Time now is 11:00pm and outside temps are 40°F. The BMW doesn't yet have a heater due to a missing control valve. Clearly I have exhausted all my options...we call for a tow truck through Geico.

Hesperia, the nearest village, is a small town. No towing companies will take the tow (48 miles) past 10pm. An hour later, we find a tow company in Rialto, California, that will take the tow, but Geico will only two to the nearest Benz dealer, in Riverside, 33 miles away. The tow company wants $15.00/mile for the extra 15 miles to our home, so I tell them let's just tow it to the dealer and be SURE to bring a flatbed.

90 minutes later, the tow company arrives with a tail-dragger wrecker, which I refused. Another 1/2 mile walk from the car to get a cell phone signal and another request to Geico roadside assistance. The same company dispatches a flatbed...

3:30am...39°F and still no tow truck. Another walk to get a signal and the truck passes me. I flag him down and we go back to the car.

I open the port on the front bumper to expose the tow hook and the driver instead pulls the car up on the bed by the tie rod ends, bending one of them visibly. I take a cell phone image and save it for the complaint I will submit later.

55mph drive behind the tow vehicle to Riverside dealership (Walter's MBZ/Porsche/Audi) who have a gated lot, so the Benz has to be dropped on the street.

5:00am, finally get family home and in bed. I sleep 2 hours and go the dealership and explain to the service manager what happened. He offers me a job (still undecided on that one.)

Spend the entire day testing connections with no results. Power available to coils and injectors but no switching ground signal. On a whim, change CPS. No change and still no communication with ECU. Dealer brings out STAR (MBZ Official) Tester and no communication is possible.

Lock car, go home..eat & sleep...

Get up today at 7:30am and make coffee and search Google for ideas. Based on research of relevant wiring diagrams, the problem is either a failed 'K-40 Main Power Relay' or a bad ECM.

Drive 12 miles to dealership and pull ECM and K-40 relay for inspection. Drive 70 miles to shop in Palm Springs and start checking the units for any sign of a failure....write this e-mail...

To be continued....