NewRevNorton

I am a Mercedes W211 owner but I am suddenly having an issue getting the vehicle to start. The key will turn within the ignition switch without any issues and all of the interior lights, accessories, and features work properly. The vehicle makes no sounds and will not crank or turn over at all. I am getting 2 cycling messages on the dash indicating "Low battery conven. functions temporarily unavailable" and "SRS Restraint system malfunction Drive to workshop". I have replaced the primary battery, auxiliary battery, and starter fuse but still unable to get the vehicle to crank. I can ground the start relay with a jumper wire and the vehicle cranks, starts, and runs perfect until the vehicle is turned off and I try to restart it. It will start by grounding the relay every time. The key fob works perfectly to unlock, lock, and open the trunk. I pulled DTC information and I had multiple codes present after clearing them initially and letting the vehicle run for a few minutes. I was getting these DTC codes:

6210 ABS braking system control
4201 increase of idling set speed
9002 Control module N2/7 (Restraint systems control unit)(Circuit 15R). No voltage when voltage present at circuit 15
9091 Communication fault with component B38/2 (Rain/Light sensor) : No response from component
9028 Fault in CAN communication with control unit N93/1 (Audio gateway control module).
930E Synchronization of the DTC memory cannot be ensured
9126 Fault in CAN communication with control unit Audio gateway
9203 Hall sensor of component M27m4 (Head restraint raise/lower motor) is faulty

I would greatly appreciate any educated support or repair suggestions. Thank you all in advanced.

NewRevNorton

I was able to drive the vehicle for a while today and I also noticed that the windshield wipers, power headrests, power sun screen, and sunroof do not work. The cruise, ESP activation/deactivation, power seats, and door lock/unlock switch all work perfectly though. I figured I would add this if it could help.

NewRevNorton

Maybe a response for Christmas?

NewRevNorton

Update: I am still able to start the car by grounding the starter relay but not only by turning the key. I have driven over 200 miles using this method while visiting family for the holidays. I have noticed that the "low battery, convenience features unavailable" message is still coming on every time I start the car but then I see a "convenience features now available" message come up shortly after driving. I still have no windshield wipers, rear headrest functions, sunroof functions, or heated seats. Hopefully somebody out there has had a similar issue or has experience with this that can offer some support.

konigstiger

"Suggestions." All codes are associated with CAN B / rear SAM, check wiring/condition of x30/7 and SAM (trunk) inclusive of all fuses. All fine next step (barring any aftermarket head unit install errors) “may” be drive authorization system each time the key is used to start the vehicle, it reads fixed serial number and rolling code. If key fails (even though you’re able to turn) the ECM prevents the engine from starting. Same problem with both keys? Not certain for 211 but you may be able to check EZS (drive authorization check) using MB STAR. EZS/EIS and/or second key fine, have malfunctioning key checked.

NewRevNorton

Great info. I was looking more to the front SAM since the starter relay/fuse and wiper relay/fuse were housed there. I will check the connection by the driver's side rocker panel as well. I checked the control panel below the head unit and it appeared that the installer of the head unit did not connect the main connector in the center of the module but I still had no change after connecting this. Thank you very much for the response.

NewRevNorton

Also, I only have 1 key .

NewRevNorton

I was able to look at the CAN B and the rear SAM this afternoon. Both appear to be fine . No visibly obvious issues. No fuses were blown. I did notice that the foam insulation under the drivers side floor mat felt damp. I left the mat lifted up to try to let it dry out. This was in the center and the rocker panel side by the CAN felt dry. Looks like the next step will be a pricey second key from the dealer or pricey diagnostics at the dealer. I haven't found any reputable Indies in my area.

NewRevNorton

I just wanted to give an update that might help someone in the future. The issue was properly diagnosed and repaired at the dealership last week. It was the EIS "electronic ignition switch".

ackiko2711

If you don't mind, can you please tell me how much it costs to fix this issue? I think I have the same problem.

NewRevNorton

The repair was roughly $850 through Mercedes.