Mercedes Power Steering Malfunction See Operator’s Manual

If your Mercedes power steering is having an electric power steering failure and displaying the warning message: Power Steering Malfunction See Operator’s Manual or Power Steering Malfunction – See the user’s manual. It’s showing an electrical failure. This warning light activates in a variety of cars: E-Class, C-Class, C Class passenger car, S Class, M Class, GLK, GL, R Class, SLK, E-Class, CLA, CLS, CL-Class, ML-Class, G Class or GLC although in other cars the power steering light may flash. You will notice that the electric power steering motor won’t help to turn the steering wheel, or in other words, it is very hard to turn the steering wheel by hand. While the malfunction can be due to a weak 12v battery, the failure can also be in the electronic power steering system. The bottom line is that the power steering has failed and is not assisting the driver. The problem can be as easy as a weak battery or blown fuse but as hard as a wrong electronic power steering motor function.

Steering Malfunction See Operator’s Manual

If this message comes up while driving:

1. Pull over to a safe location and turn off the ignition.
2. Wait at least five minutes and restart the car. Keep ignition and lights off during this period.
3. Restart engine. In many cases, the error message may reset on its own.

Although new Mercedes-Benz cars have electric power steering, they keep a mechanical connection to the steering rack. Therefore, our recommendation is to refrain from driving and make sure you can use brute force to turn the steering wheel when necessary. The steering motor will make it harder, but without the electrical assistance, you should have enough strength to manage.

Common Problems

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The following problems are known to cause problems in Mercedes-Benz with an electrical power steering system.

Weak 12 Volt Battery

In Mercedes-Benz cars, we often experience a failure if the battery is partially discharged or the voltage regulator breaks down. So, if you drive the car for about one hour, the 12-volt battery will be charged, and at the same time, the intelligent battery charger will charge the battery also. If the message comes up more and more times and does not clear after 1 hour of driving the car, the 12-volt battery must be checked.

Blown Fuse

There is a 125 A pre-fuse that feeds the power steering motor. This fuse can blow, disabling the electric power steering assist. If the fuse blows, it indicates a problem or a lousy steering motor. The fuse is located in the pre-fuse box in the engine bay.

Steering Motor

The power steering motor can fail, making the steering very hard to turn and triggering steering malfunction. See the Operator’s Manual error message on the dashboard. The steering motor is mounted on the steering rack and easily replaced.

Software Issue

The software for the electric steering may be the culprit and needs to be updated. You must take the car to the dealer to update the module. Call your local dealer to check if an update is available for your steering system.

Ground Issue

If your Mercedes-Benz has electric power steering and you have a Power Steering Malfunction warning, the second most common issue that can cause this warning is a loose or corroded ground wire in the power steering rack. A loose positive connection at the fuse box feeding the power steering electric motor can also be problematic.

Steering Angle Sensor

Failure of electronic power steering can also result from failure of steering angle sensors. Using a full system scanner, the fault codes from the computer can be read out to diagnose whether the steering angle sensor is the signaling element involved.

Recall

Over 28,000 model-year 2015 Mercedes-Benz C300 and C400 4Matic sedans manufactured between 27 Jan. 2014 and 1 Dec. 2014 were recalled by Mercedes-Benz USA LLC because the in-vehicle software for the electric power steering control unit was coded with the wrong default idle speed of 1,050 rpm.

Because of this issue, electric power steering assist could be lost, increasing the need for steering effort, especially at low speeds, and increasing crash risk. If your car has this issue, review the agencies’ recalls on their websites or use the search function for your make, model, and engine size. If you find an open recall for your car, go to the vehicle safety website, enter your VIN for recalls, and immediately address the recall.

How to diagnose the Mercedes Steering Module

To read and clear all your vehicle’s control modules, you will need a scanner such as the YOUCANIC Full System Scanner.

1. Connect the scanner to the diagnostic port under the dashboard.
2. Turn on the ignition.
3. Go to Mercedes > Select Model > Control Units
4. Select Chassis, then Select ES – Electric Power Steering
5. Scroll down to read codes and press enter. Review all the codes. Write them down for future reference.
6. If you only have stored codes, select Clear Codes to erase them. If codes are present, fix the underlying problem.

Frequently Asked Questions

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