[Teutonic]

I have a 2010 ML350 (gas) with 100k miles.

The ABS and ESP Warning Light have both come on. I scanned the ML with my new Autel DiagLink scanner and it reported the following fault codes:

ESP-Electronic stability program, Fault | 6
5101 L6/1 (left front speed sensor) : Carry out visual inspection. CURRENT
5102 L6/1 (left front speed sensor) : Check wheel bearing(s). CURRENT
5103 L6/1 (left front speed sensor) : Carry out visual inspection. CURRENT
5104 L6/1 (left front speed sensor) : Clean multipole ring and replace if necessary.CURRENT
5105 L6/1 (left front speed sensor) : Implausible wheelspeed CURRENT
5106 This fault can be ignored and erased. CURRENT
Event 6001 the supply voltage of the control unit is too low (undervoltage).

Where is the "left front speed sensor"? What should I look for when doing a "visual inspection"? Do these codes look valid? Any thoughts on what to do next? To repair? Next steps?

Thanks in advance for any advice and assistance!

Sent from my iPhone using Tapatalk as best I could.

-Brian
Lima-Lima-Mike-Foxtrot

 

[SkippyJasper]

Found this.

Hi all,



I have a 2008 ML320 (164.122), were ABS/ESP says it is not available. I already replaced ALL rpm sensors, but front left wheel is still strange.

I have a iCarsoft scanner, and if I read ESP -> running values -> rpm sensors, I can see that all four report speed, *but* front left speed is strange, goes up and down as the wheel turns, while the other three wheels show a 'constant' speed. I have done the test at multiple speeds, from 10km/h to 40km/h.



If I reset the errors in ABS/ESP, and start driving the car, the front right wheel brakes get engaged like crazy, kind of expected, as ESP sees left wheel "stopping".



Currently, I am thinking that the magnetic ring might have some damage. The car was bought used 2 years ago, and was until one month ago that the ABS/ESP & front wheel problems started. I also discovered that it had a frontal collision of some type, cause I discovered a few mis placed/ broken parts while changing the rpm front sensors. Has anyone seen something like this before? I know that the wheel bearing comes with the magnetic ring.



Any suggestions?



I already read the thread " ML320 CDI ongoing self braking problem??? ", but does not look like my problem.





Thanks.

 

[43sqd]

Yes the codes are valid.

Jack up the left front wheel and remove tire and on the rear of the steering knuckle you will see L6/1. Check wire cable for any damage.

If not then remove the bolt and try to remove the sensor by twisting it back and forth. Do not use screw driver to pry it up, spray with Liquid Wrench and try again.

The PDF below is only shown to give you the location of the speed sensor.

 

[Teutonic]

ABS and EAP Warning Light On

43sgd,

If the sensor is not damaged, does cleaning it usually fix the problem? Was wondering I should just go ahead and replace the sensor, since I'm going to the process of jacking up the ML, removing the wheel and removing the sensor?

Also, where is a good source for the part, if it needs replacing? Is this something I can get at autozone? Or need to get from the dealer? A cursory search showed them listed on Amazon.

-Brian

 

[Teutonic]

ABS and EAP Warning Light On

I removed he wheel, inspected the sensor cable, removed, inspected and wiped clean the sensor (and attempted to clean the hole the sensor goes in to).

The two ABS and ESP Warning lights remained ON.

I tried to use my scanner to clear the codes, but received the message, "Fault memory could not be erased. The preconditions for clear code were no met."

What do you think is the next step? Replace the sensor? Are the ones from Autozone and NAPA good sensors? Or should I shell out the bucks for the part at the dealer?

Also, the fault codes mentioned to check the bearings. I did a visual and tried to shake the tire/rotor to see if there was any slack. There was none. Other than that, that's all I know on how to check for a bad wheel bearing.

Thoughts?


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[43sqd]

Did you follow the instructions starting on pg. 39 of the owner's manual.

After clearing codes, turn ign. off, wait 20 secs. and turn key on and check for codes.

 

[Teutonic]

Did you follow the instructions starting on pg. 39 of the owner's manual.

After clearing codes, turn ign. off, wait 20 secs. and turn key on and check for codes.

43,

Are you talking about the chapter in the owners manual about Driving safety systems? It describes how to turn the ESP on/off, with the engine running, by using the ESP switch on the dashboard.

I will try to turn off the ESP warning light on the dash using this switch and let you know the results.

I tried to clear the fault codes once before, but received the message, "Fault memory could not be erased. The preconditions for clear code were not met."

Thoughts?

-Brian

 

[43sqd]

Brian, it's about how to clear codes. Maybe your manual shows a different page.

 

[Teutonic]

After Clearing the Fault Codes, Turned Ignition Off, waited 20 seconds, and Scanned again. The same 6 fault codes showed up and the warning lights on the instrument cluster remain.

What is the next step? Replace the wheel sensor?

-Brian

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[43sqd]

Does it still say that the preconditions were not met?

What is your full vin#?

 

[Teutonic]

Does it still say that the preconditions were not met?

What is your full vin#?

Yes, I still get the same message about preconditions not being met. Also, I don't get the message reminding to turn off the ignition for 10 seconds before clearing the codes like I did with the other codes.

What are the preconditions? How does the ML know they were not met?

The two warning lights remain.

ML350 VIN: 4JGBB5GB2AA536981

Also, I called the local MB Dealership to see if they had the LF wheel sensor in stock. The parts guy told me that this sensor had been redesigned and MB now requires both the wheel sensor and brake pad wear sensor to be replaced at the same time. And you get a new "bracket" to mount them. Cost of the wheel sensor, brake sensor, and bracket is $244. What do you think about that? Sounds odd to me, since the sensors are not on the same system - one is ABS and one is Brake?

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[43sqd]

Yes, I still get the same message about preconditions not being met. Also, I don't get the message reminding to turn off the ignition for 10 seconds before clearing the codes like I did with the other codes.

What are the preconditions? How does the ML know they were not met?

Brian, you are making me work too hard, I was very clear about clearing the codes. After clearing the codes, turn ig. off for 10 secs. and then recheck.

You must read your owner's manual concerning reading and clearing codes. See if there is a section about prerequisites and you must be doing something wrong in your procedure If you do not, contact Autel and ask them.

If you want to change the sensor, here is the part number.

 

[Teutonic]

43,

I know what you mean - I feel I'm running in circles, too.

I've read the Autel user manual several times. I've even downloaded the latest version (same as the one I have in paper) from Autel's web site and read that one. They both give the same instructions for clearing codes:

1. Have the key in the ignition in the ON position with the engine OFF.
2. Read the codes.
3. Then clear the codes.
4. Turn OFF the ignition and remove the key.
5. Wait 10 seconds.
6. Turn ignition ON.
7. Perform scan to see if codes reappear.

This procedure worked for other faults in other modules, except the ESP. With the ESP, when I try to clear the codes, I get the message about the "Preconditions" not being met, so I'm not able to do the rest of the steps. I am researching this "preconditions" message and will probably call Autel as you advised. I hope they have a support line.

I called the Mercedes dealership yesterday with the idea of purchasing the speed sensor and replacing it (approximately $128) to see if that fixed the problem. But, they would not sell me the sensor without including the brake pad wear sensor and bracket (basically, everything in the photo you included in your last post). That was $244. I balked at purchasing all of those parts without knowing for sure if that would fix the problem.

This morning, I went out and started the ML, first thing. i noticed something that I've noticed before - when the ML is cold (not started recently), or been sitting overnight, the engine turns over slowly, as if the battery is weak. But, it starts on the third "revolution", so I thought it might just be normal for this model. This is my wife's car, so I don't normally drive it and when I do, the engine is 'warm'. The "slow" start only happens when I'm the first person to drive it in the morning. Just to clarify, when i say "slow" start, I mean the engine turns over slowly for two times, but "catches" and starts every time on the third revolution. It doesn't turn over several times before starting. But, its very noticeable when compared to my ML320 or 560SL which cranks strong and starts instantly.

The possibility of the battery being drained overnight has got me to thinking. After all, one of the original fault codes in the ESP was "Event 6001 the supply of voltage to the control unit is too low (undervoltage). I'm wondering if the battery is bad (its three years old) or if there is a "vampire" that is slowly draining the voltage overnight.

Do you think low voltage could be causing these two warning lights and the ESP faults?

I have a multimeter to check the battery. I'm just not sure of the good procedure on this ML. Since it has a battery and a 'backup" battery, the test needs to isolate the main battery. Can you disconnect the negative terminal and perform the voltage test, without "killing" or erasing any of the electronic components? I haven't found a clear thread on how to check the voltage on the battery. Should I just take it to Autozone and let them do a load test?

You can see, that I'm thinking of pursuing the possibility of the battery/low voltage being the problem. If I can eliminate the battery, then I can focus back on the speed sensor. What do you think?

Thanks for your help - I know this is frustrating, because it is frustrating me. I've never had a problem like this with my ML320 or my 560SL.

-Brian

 

[Teutonic]

43,

I put a voltmeter to the positive and negative terminals in the engine compartment and read the voltage - 12.4volts. I also checked the voltage directly on the batter (with the cables still connected to the terminals) and the voltage was 12.4. Lastly, I started the engine (to check the voltage from the alternator to ensure the battery was receiving a good charge) and checked the voltage on the terminals in the engine compartment. The alternator is putting out over 14 volts.

The Carfax showed the battery was replaced at the dealership four years ago.

From what I've read on other threads, a battery needs replacing if it doesn't put out a minimum of 12.7 volts. True? What is your opinion?

If the battery needs replacing, do you recommend an MB battery only, or a comparable battery from a reputable brand?

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[43sqd]

Tomorrow morning, without starting the eng., check to see what the battery voltage is. If it's below 12.4v take it for a 1/2 hr. hwy. drive with no consumers on. Shut off eng. and read voltage.

The following morning read battery voltage.

Slow starting can be attributed to low battery voltage at start-up or a drain on the battery or a faulty starter. So everything depends on voltage after shut down and what it is the following morning.

As for the parts for the speed sensor, wear sensor and bracket, $244 is way out of line. The speed sensor is $125. Did you ask the dealer why you had to buy the other two items?

 

[Teutonic]

43,

I will do that, first thing in the morning.

Note: All of the 12.4 volt readings in the previous post were taking after driving around town, including the trip to the Mercedes Dealer. But, the radio, heater blower, lights, etc. were all running, too.

-Brian

 

[43sqd]

12.4 Volts should have no problem starting. If you have that in the morning and it is slow start, it is the starter.

 

[Teutonic]

43,

Th ML doesn't have trouble starting, it's just the first two "revolutions" are slow before the ignition catches and starts the engine. This, to me, is a sign of a weak battery.

I checked the battery voltage first thing this morning and it is 12.3 volts. A little lower than than the 12.4 the battery was putting out at mid-day, yesterday, after driving for over an hour.

I'm guessing the next step is to replace the Battery? If so, do you prefer having the Dealership replace it. Do you recommend replacing the Auxiliary Battery at the same time? What do you think about aftermarket batteries other BenzWorld member mention (Size H8 Platinum AGM Battery from Advance Auto Parts, made by Johnson Controls)?

Sent from my iPhone using Tapatalk and two Thumbs.

 

[43sqd]

You were asked to provide three voltage readings and you did not. See a professional mechanic because I am wasting my time and effort with you.

Tomorrow morning, without starting the eng., check to see what the battery voltage is. If it's below 12.4v take it for a 1/2 hr. hwy. drive with no consumers on. Shut off eng. and read voltage.

The following morning read battery voltage.

 

[Teutonic]

You were asked to provide three voltage readings and you did not. See a professional mechanic because I am wasting my time and effort with you.

Tomorrow morning, without starting the eng., check to see what the battery voltage is. If it's below 12.4v take it for a 1/2 hr. hwy. drive with no consumers on. Shut off eng. and read voltage.

The following morning read battery voltage.

My apologies...I'm certainly not trying to be difficult with someone who is offering to help. I guess I had thought I had performed the procedures you suggest in Post 14 and 18.

Thank You again, for your help so far, and there are no hard feelings for your decision to drop out of this thread.

-Brian