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When all this happened, she shut off both times. I had to wait a day or two before it would start again. I replaced the auxiliary battery, and the battery and charging system checked out OK. I used a BlueDriver scan tool to check and clear codes, but it didn't clear all the codes. The scan tool said that i needed to clear codes with the engine off, but the scan tool wouldnt vonnect with it off.. I took it to a mechanic to run diagnostics and clear codes. Thinking their scan tool would be more sophisticated than mine. I just replaced #6 coil after this.
Welp, I drove around yesterday for about 3 hours(DoorDash driver) with no problems. Then today it started throwing the ESC fault. I would clear it and it would come back. Then later it started throwing everything again, but it never shut the engine off. All the dash lights would come on and the speedo would go crazy. All of this would come and go and come on again. I could REALLY use some electrical help. I'm not trying to blow a bankroll at the dealer. Thanks!!
When all this happened, she shut off both times. I had to wait a day or two before it would start again. I replaced the auxiliary battery, and the battery and charging system checked out OK. I used a BlueDriver scan tool to check and clear codes, but it didn't clear all the codes. The scan tool said that i needed to clear codes with the engine off, but the scan tool wouldnt vonnect with it off.. I took it to a mechanic to run diagnostics and clear codes. Thinking their scan tool would be more sophisticated than mine. I just replaced #6 coil after this.
Welp, I drove around yesterday for about 3 hours(DoorDash driver) with no problems. Then today it started throwing the ESC fault. I would clear it and it would come back. Then later it started throwing everything again, but it never shut the engine off. All the dash lights would come on and the speedo would go crazy. All of this would come and go and come on again. I could REALLY use some electrical help. I'm not trying to blow a bankroll at the dealer. Thanks!!
Usually when it throws so many codes all at once, it is a bad 12V battery and/or aux battery.
Thank you for another forum member that PMed me and reminded me that OP has already changed the battery and aux battery, my senior moment for not noticing that sentence. Then I wonder if the alternator is doing a good job keeping the battery sufficiently charged for stable voltage to the electronics?
Welp, I drove around yesterday for about 3 hours(DoorDash driver) with no problems. Then today it started throwing the ESC fault. I would clear it and it would come back. Then later it started throwing everything again, but it never shut the engine off. All the dash lights would come on and the speedo would go crazy. All of this would come and go and come on again.
First monitor the charging system in real time as @Bill F recommends while driving and note what it’s doing when the problems show up.
If the charging voltage checks out okay then it could be the front SAM or even the ECU. But before going down that rabbit hole, carefully unlatch the ECU connector and examine it for signs of oil. Oil has been known to wick from the cam magnets into the wiring harness and even get to the ECU. The harness connector can be sprayed with electrical contact cleaner, but the ECU cannot. Let’s hope that looks okay.
Not sure where to put this one in the trouble shooting because I have test equipment a DIYer won’t have. But before you throw up your hands in disgust consider it.
If you have a lot of miles on the GLK, even if the voltage looks good there’s a chance the alternator brushes and slip rings are worn and the supply current is getting very noisy. The voltage monitor in the head unit won’t see this noise and neither will the scanner unless it allows you to plot the voltage on a graph. The solution is to change the voltage regulator because it contains new brushes.
First monitor the charging system in real time as @Bill F recommends while driving and note what it’s doing when the problems show up.
If the charging voltage checks out okay then it could be the front SAM or even the ECU. But before going down that rabbit hole, carefully unlatch the ECU connector and examine it for signs of oil. Oil has been known to wick from the cam magnets into the wiring harness and even get to the ECU. The harness connector can be sprayed with electrical contact cleaner, but the ECU cannot. Let’s hope that looks okay.
Not sure where to put this one in the trouble shooting because I have test equipment a DIYer won’t have. But before you throw up your hands in disgust consider it.
If you have a lot of miles on the GLK, even if the voltage looks good there’s a chance the alternator brushes and slip rings are worn and the supply current is getting very noisy. The voltage monitor in the head unit won’t see this noise and neither will the scanner unless it allows you to plot the voltage on a graph. The solution is to change the voltage regulator because it contains new brushes.
Happy hunting!
I disconnected the ECU when I needed clearance to get the #6 coil removed. I noticed oil in the ECU connection and cleaned it the best I could. I will try spray cleaner you mentioned and go from there.
I disconnected the ECU when I needed clearance to get the #6 coil removed. I noticed oil in the ECU connection and cleaned it the best I could. I will try spray cleaner you mentioned and go from there.
I think this is a big problem. This is a fairly good video describing it.
I’m not on board with the video’s explanation of what causes the wicking but the details aren’t important. The facts that the cam magnets and the position sensors are the source are correct.
Check the cam position sensors and the cam magnets. They may all need to be replaced. Then the crankcase ventilation system needs to be inspected and cleaned up if necessary. Complete clean up could come down to unwrapping some of the accessible harness and spraying with contact cleaner. Hopefully the oil hasn’t penetrated the ECU pin contacts an gotten inside.
Aftermarket anti-wicking loops are available as a future preventative for a total of ~$200.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
