The ABS malfunction indicator comes on as soon as my 300E attains speed of about 5, 6 km/h then never goes off until ignition is off. I cleaned the speed sensors and checked their wires but still the problem remains.

Function of the ABS was also tested. Sudden brake was applied when my car was at speed. The car stopped without any lock and black trail behind. ABS seems normal except the brake pedal excessively pulsates when the car is at low speed, i.e. less than 5, 6km/h. Pulsation stops when the indicator comes on.

I suspect the OVP but except the above thing the car runs perfect.

Any thoughts?

Check your ovp.

OVP (most likely) or different sized tires. Happens to me in the past. My car was lowered by PO with 245/45/17 rear and 215/45/17 front - always got ABS light on highway, even after replacing OVP. Changed front tires to 225/45/17 - all good now.

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1987 300D Turbo 170K (sold)
1990 300E
1992 300D 2.5 Turbo
2003 Audi A6 4.2

It sounds like a bad sensor, most likely the right front one.

With a simple voltmeter you can check the sensors, attach to the sensor wire and turn the wheel. They should give the same voltage.

Rob

Check the ABS grooves that the sensor reads from if they are filled with dirt or rust this can happen.

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600SEL '91
300E 4Matic '88
240D '83
280SE '77
350SE '73
The most complex systems can fail in the simplest way.
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i agree with everyone here,simple things first,clean the wheel sensor pick up on the back of the hub, with brake clean,make sure it looks like a clean gear after,then test te ohms and resistance between both sensors,with an ohm meter or voltage meter,while spinning wheel ,possible defective sensor,sometimes water works into them and causes this condition,remember your abs will not work when the light is on.

Not necessarily. If the OVP is the cause of the light, the ABS still functions fine. At least that was my experience for both my cars which had the issue at purchase.

That might be an easy way to diagnose the issue. If the ABS does not function on hard braking, look into the sensors. If it does function, look into OVP.

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2016 Monsoon Gray Audi Allroad - 21k
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