Date registered: Jan 2013
Vehicle: 65 220SEb, 97 SL500, 98 E320 Wagon, 2002 ML500 - former W108/W112/W114/W123/W124/W126/W140/W220
Location: Tampa, FL
Mentioned: 14 Post(s)
Quoted: 1052 Post(s)
BAS/ESP/ETS/ABS - Yet Another One of These Threads...
Sorry to do this, but I've spent the better part of the weekend researching my issues and found little to nothing that corresponds with other threads for similar warnings. So bear with me and I'll do my best to present everything as best i can.
As a preface, I'm a 30 year Mercedes owner and a former high-line mechanic, so my diagnostic skills are probably at the higher end of the scale. I have a STAR/DAS system so I can access codes, faults and see active data as required.
So why could this be so darned perplexing????
Here's the deal:
BAS comes on randomly. Can often clear it with the "lock to lock" steering wheel turning. Will often come on maybe 10-15 miles later.
BAS/ESP/ETS/ABS will come on as a group, accompanied by the "Brake" warning light. This is accompanied by the peeping alarm that continues to sound as long as the car is moving. Come to a stop, lights remain on, peeping stops.
Running a full scan using the DAS system, the only faults that come up are C1140 (steering angle sensor) and C1306 (right rear axle solenoid valve).
ABS pump has been checked and it runs by doing an activation though DAS.
Voltage tests as prescribed in Star Tekinfo for the steering angle sensor are correct. Looking at actual values for the steering angle sensor in DAS reflect correct values. Steering has been zeroed and cleared both using DAS and with the "lock to lock" method as well.
Car was aligned recently (again, steering is centered properly and the steering angle sensor reflects this) and I have the same tires with lots of tread all the way around.
I replaced the brake light switch and installed it per the bulletin, as I had one on the shelf.
I suspect I'm looking at multiple issues here possibly, and this is why I say this:
I replaced a right rear caliper last week. I bled the system with my pressure bleeder, but the first time I put my foot on the brake pedal it went to the floor. Once it returned I had pedal, but the travel seemed long and if I maintain pressure on the pedal it will leak down very slowly. It's also spongy.
I'm wondering if when the pedal went to the floor the cups in the master cylinder might have been damaged. Based on this I'm pretty sure I need to replace the master cylinder.
Differential pressures at the master cylinder were checked in DAS and they're right on the money, so I don't see where that would cause an issue, but the leaking down can't be anything but the master cylinder. However, if that was leading to some of these alarms why doesn't it occur when the brakes are applied rather than just coming up as what appears to be random intervals?
The only other thing I can think of to toss into the mix is that the ECU box blower is not working. Totally dead, I've got a replacement coming later this week. I'm also wondering if it would be wise to disconnect the battery, disconnect all the modules in the ECU box and clean the connectors with contact cleaner.
And a proverbial red herring:
No horn. Fuses are good, horns are good. I've wondered if someone has been into the steering column and messed with the clock spring and/or things in that neighborhood. I'm not getting any error codes for airbags or anything like that, however.
I'm open to any and all suggestions at this point. I'm practically stumped.
Last edited by LWB250; 05-27-2019 at 05:53 PM.