Flashing Yellow Triangle supposedly after Wheel Change ML320 W164

[NP89]

Hi all,

New to the forum. Just bought a 2008 W164 ML320 AMG.

I believe the car originally had 19" wheels which have now been replaced with 20" wheels.

New tyre sizes are Fronts: 265/45/20 and rear 275/40/20.

I get the flashing yellow triangle indicating a traction fault but definitely not a genuine traction issue i.e no wheel slippage or spinning. My first thought was wheel speed sensor going bad. However, the seller is adamant that the fault is to do with the new wheels and was fine before - Interestingly if you drive for a few miles sub 45mph and then accelerate up to normal speeds, the fault never reappears after that until you turn the car off and on again, which suggests some sort of automatic calibration happens and not the wheel speed sensor at fault. Obviously this is not practical longer term.

Has anyone ever experienced this or know the fix? image attached to show wheels if it helps!

Thanks

 

[Smiley]

The tyre sizes don't look correct. I don't know what an ML on 20s should have on it - but the combo you have gives about an 18mm difference in diameter and my guess is that is too big for the car electronics to deal with - the wheels are turning at sufficiently different speeds to make the car think that one is slipping - hence the traction control light.
Find out what the recommended tyre sizes are from MB and change either the front, rear or both.
Or put the 19s back on; presumably they were fitted with the correct tyres.

 

[NP89]

The tyre sizes don't look correct. I don't know what an ML on 20s should have on it - but the combo you have gives about an 18mm difference in diameter and my guess is that is too big for the car electronics to deal with - the wheels are turning at sufficiently different speeds to make the car think that one is slipping - hence the traction control light.
Find out what the recommended tyre sizes are from MB and change either the front, rear or both.
Or put the 19s back on; presumably they were fitted with the correct tyres.

Yea I just measured the rim depths and they are 8.5" all round...... so no need for the different profiles I suspect. I dont have the 19" wheels sadly so next step is to swap out the wider rear tyres to match the fronts and see if it solves it. Will update!

This is the reference table:

M Class (W164)​	Rim Dimensions	Offset	Tyre size				Brand
	17x7.5	56	235/65R17				Mercedes-Benz
	18x8	60	255/55R18				Mercedes-Benz
	18x8		235/60R18				Brabus
	18x8		<285/50R18				Brabus
	19x8	60	255/50R19				Mercedes-Benz
	19x8.5	58	255/50R19				AMG
	19x8.5	58	255/50R19	19x9.5	56	285/45R19	AMG
	19x8.5		255/50R19				Brabus
	19x9.5	46	295/45R19				AMG
	19x9.5		285/45R19				Brabus
	20x10	46	295/40R20				AMG
	20x8.5	60	265/45R20				Mercedes-Benz
	20x9.5		265/40R20				Brabus
	20x9.5		275/40R20				Brabus
	22x10		265/35R22				Brabus
	22x10		295/30R22				Brabus

 

[Smiley]

I'm sure that will fix it. Are the 265/45/20s the size recommended by MB? No point buying new tyres only to find that they are not correct.

 

[Smiley]

The tyre sizes are usually inside the fuel filler cap

 

[BTB 500]

There's a fitting chart that lists all the 'official' wheel/tyre combinations for each model here:

Mercedes-Benz Fitting Chart and Wheel Fitment Guide | Alloy Wheels Direct

Comprehensive wheel fitting chart and guide for Mercedes. Information on tyre and wheel sizes, offsets and PCDs. Find out which wheels will fit your vehicle

www.alloywheelsdirect.net

 

[Petrol Pete]

OP , you say you want to swap out the rear tyres to match 'width' on the front . Is that a typo ? Width will make little or no difference .

It's circumference (sidewall height) that needs to be 'balanced ' to whatever the cars software is reading at any one time.

The wheels look very odd in the photo , it might just be the camera angle or the suspension is set on the highest position.

As an aside many years ago I had a company car with crude ABS (Vauxhaull vectra) a front tyre was damaged and replaced , the ABS light kept coming on until they replaced the opposite tyre to match up the different circumfrence of the new tyre.

 

[NP89]

Thanks everyone, to update for anyone having this issue in the future, fitting the correct rear tyres with matching profiles fixed this!