dmont

So far this car has been very good to me. However, I've been dealing with a few issues with my 2011 ML350 4 Matic with 160k miles and I'm wondering if anyone can shed some light on what might be happening.

--Strange hesitation or bucking once the car is warmed up. Usually on acceleration, and sometimes experienced while in reverse.
--Excessive tire wear on the front tires. Especially the front right.
--5140 B34 Brake pressure sensor code
--5126 L6/3 Left Rear Speed Sensor Code
--5116 L6/2 Right front speed sensor code

Done so far:
I replaced the wheel speed sensors and attempted to clear the codes. I have not yet manually tested with a multimeter to see if the sensors are sending a signal. I don't think my OBD scanner can clear the code. (Innova 7100P - btw, don't buy this scanner, or any Innova product)
I changed the transmission fluid.

To do:
I'm going to check on the wheels sensors this weekend. I'll also schedule an alignment to check on the existing alignment to see if that's the culprit.
I noticed my front driveshaft needs to be replaced as the boot is torn.
I'm wondering if the difference in tire tread is causing this issue as the 4Matic versions require similar tire tread on all 4 wheels.

KlausPA

Don't forget to change the TC fluid as well.

wannawagon

often the abs codes won’t clear immediately (come up as not fixed so can’t clear) but they often clear on a short drive.

perhaps temporarily over inflate (refer tyre maximum) on the worn tyres. Maybe have the ones with good tread being lower pressure may make rolling diameters the same.

unsure of brake pressure sensor?

expl0rer

I doubt your tire wear is the problem. Your tire diameters should be within 1%. Assuming all of your tires are the same brand/model. If you have a fully worn tire @2/32 and a brand new tire @10/32, the difference is 1/4 inch or 0.25 inch.

To figure out your diameter, use this formula. Applies to new tires at full 10/32 thread.

Tire width × tire height ÷ 100 × 2 ÷ 25.4 + diameter of the wheel = diameter of the tire (in inches)

Example for a 275/50R20 tire.

275×50÷100×2÷25.4+20=30.83 inches

If your diameter is greater than 25, then you're within the 1% difference.

Are the tires on the same axle worn similarly and have the same thread remaining? Also possible that the new sensors might be faulty.

expl0rer

Forgot to ask if the new sensors were from MB or aftermarket. The consensus is to use MBs. I used Delphi to replace mine and found the harness connection less than perfect but they're performing well otherwise.