What Does "Power Steering Malfunction" Mean on a Mercedes-Benz?
A power steering malfunction mercedes warning appearing in your instrument cluster or MBUX display means the vehicle's Electric Power Steering (EPS) system has detected a fault and is operating in a degraded or disabled state. This is not a cosmetic warning — it directly affects your ability to steer the vehicle safely, particularly at low speeds and during parking maneuvers.
Mercedes-Benz models from the W205 C-Class, W213 E-Class, W222 S-Class, X253 GLC, and W166/W167 GLE all use electrically assisted steering systems controlled by a dedicated EPS control unit. When the system detects an internal fault, sensor failure, voltage irregularity, or communication error over the CAN bus, it triggers the "Power Steering Malfunction" message and may reduce or cut assist entirely. Understanding the root cause requires reading the stored fault codes — not guessing.
Common Causes of Power Steering Malfunction on a Mercedes-Benz
1. Faulty or Failing EPS Control Unit
The Electric Power Steering control module is the most frequent cause of a mercedes eps malfunction on higher-mileage vehicles. The module manages motor torque, steering angle, and driver input simultaneously. Internal component failure — often heat-related — causes the unit to log communication faults and disable assist. Affected platforms include the W205 and W213, particularly on models built between 2015–2020. Replacement or remanufacturing of the EPS module is typically required.
2. Defective Steering Angle Sensor (SAS)
The Steering Angle Sensor feeds real-time wheel position data to the EPS module, ESP, and Pre-Safe systems. A failed or miscalibrated SAS will trigger the power steering malfunction warning alongside related stability control faults. This sensor sits on the steering column and is commonly disturbed after wheel alignments, battery replacements, or steering component work. Recalibration using Mercedes XENTRY/DAS software is mandatory after replacement.
3. Low or Unstable Battery Voltage
The mercedes electric power steering malfunction warning is frequently voltage-related. The EPS motor draws significant current, and a weak 12V battery, failing AGM battery, or failing IBS (Intelligent Battery Sensor) can cause momentary voltage drops that force the system into limp mode. This is especially common on S-Class W222 and GLE W167 vehicles with multiple power-hungry systems active simultaneously. Test battery health and charging system output before replacing any steering components.
4. EPS Motor or Torque Sensor Failure
The electric power steering motor is integrated into the steering rack assembly on most current Mercedes platforms. Internal winding failure, brush wear, or a faulty torque sensor embedded in the steering column will cause the system to detect incorrect or absent assist requests. This typically manifests as heavy steering at low speeds before the full warning appears. On 4MATIC models, the additional load from the drivetrain can accelerate wear on these components.
5. CAN Bus Communication Fault
The EPS module communicates over the chassis CAN bus with the ESP module, instrument cluster, and Collision Prevention Assist system. A wiring fault, corroded connector at the steering column harness, or a failing CAN gateway module can cause the EPS unit to lose communication and default to a no-assist state. This type of fault often presents intermittently before becoming permanent and will generate both EPS-specific and bus communication fault codes simultaneously.
What to Do When You See This Warning
When the "Power Steering Malfunction" message appears, reduce speed immediately and avoid highway driving if steering effort has noticeably increased. Pull over safely if the steering feels heavy or unresponsive. Do not ignore this warning — a complete loss of power assist at low speed is a serious safety hazard. Check whether any secondary warnings are displayed alongside it, such as ESP Inoperative or Stop Vehicle — Shift to P, which indicate a more severe system failure. Restart the vehicle; if the warning clears, note the conditions under which it appeared and scan for stored fault codes as soon as possible.
Even if the warning disappears after a restart, stored fault codes remain in the EPS control unit memory. A mercedes benz power steering malfunction that clears temporarily is still a developing fault — intermittent failures almost always worsen without intervention. Do not delay diagnosis. Driving with a compromised EPS system also affects the accuracy of Active Lane Keeping Assist and Active Steering Assist on equipped models.
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Mercedes stores specific EPS fault codes behind this warning that won't show up without a scan. The Launch X431 CR319 reads Mercedes-specific codes in under 30 seconds — compact enough for the glove box, no subscription required.
→ Get the OBD2 ScannerHow to Diagnose Power Steering Malfunction on a Mercedes-Benz
Accurate diagnosis of a power steering malfunction mercedes requires fault code retrieval first. The specific code stored in the EPS module will tell you whether the failure is electrical, mechanical, sensor-related, or a communication issue — and will prevent unnecessary parts replacement. Follow these steps in order.
Step 1: Scan for fault codes. Connect an OBD2 scanner capable of reading Mercedes-specific chassis codes to the OBD2 port (located under the dash, driver's side). Read all codes from the EPS/Servolectric control unit, not just generic engine codes. Note every code present — multiple codes often point to a root cause like a voltage fault or CAN bus issue rather than isolated component failure.
Step 2: Test battery and charging system voltage. Before replacing any steering components, measure the 12V battery voltage at rest (should be 12.6V+) and under load. Test the IBS sensor response and alternator output. A battery delivering less than 11.5V under cranking load is a likely contributor to the mercedes eps malfunction and should be replaced with the correct Mercedes-spec AGM battery. Coding the new battery to the vehicle via XENTRY is required on most platforms.
Step 3: Inspect the EPS harness and steering column connector. Locate the multi-pin connector at the base of the steering column where the EPS motor harness and Steering Angle Sensor wiring connect. Look for corrosion, bent pins, or chafed insulation. On W205 and W213 models, this connector is a known failure point and can cause intermittent CAN communication faults that mimic EPS module failure. Clean or replace as necessary.
Step 4: Perform EPS module live data and actuator tests. Using Mercedes XENTRY/DAS or a compatible professional scan tool, access live data from the EPS module to monitor torque sensor input, motor current draw, and system voltage in real time. Run the available actuator test to verify the EPS motor responds to commanded inputs. If motor current is absent or erratic and wiring is intact, the EPS rack and pinion assembly or the module itself requires replacement.
Mercedes-Benz Fault Codes Related to Power Steering Malfunction
| Code | Description | Likely cause |
|---|---|---|
| C1511 | EPS — Electric Power Steering System Malfunction | EPS control module internal fault or motor failure |
| C1513 | EPS — Supply Voltage Too Low | Weak AGM battery, failing IBS sensor, or alternator fault |
| C1560 | Steering Angle Sensor — Signal Implausible | Defective or uncalibrated Steering Angle Sensor (SAS) |
| C1001 | EPS — CAN Communication Fault with ESP Module | Chassis CAN bus wiring fault or corroded steering column connector |
FAQ — Mercedes-Benz Power Steering Malfunction
Can I drive my Mercedes with the power steering malfunction warning on?
Short distances at low speed are possible if steering effort is only slightly increased, but it is not advisable. If the EPS system has fully disabled assist, the steering will feel extremely heavy — especially during parking and low-speed maneuvers. Do not drive at highway speeds with this warning active, as a sudden loss of assist at speed is a serious safety risk.
Why does my Mercedes power steering malfunction warning appear and then disappear?
Intermittent warnings are typically caused by voltage drops, a loose connector at the steering column, or an early-stage EPS control unit fault. The warning clears when conditions temporarily improve, but the underlying fault code remains stored. Scan the EPS module immediately — intermittent failures on the W205, W213, and GLC X253 commonly become permanent without repair.
How much does it cost to fix a Mercedes electric power steering malfunction?
Cost varies significantly by root cause. A battery replacement runs $200–$400 including coding. A Steering Angle Sensor replacement is typically $300–$600 with recalibration. A remanufactured EPS rack and pinion assembly for a W205 C-Class or W213 E-Class ranges from $800–$1,800 in parts alone, plus labor. Always confirm the root cause via fault codes before committing to expensive component replacement.
Does a Mercedes power steering malfunction affect other safety systems?
Yes. The EPS system shares data with ESP, Active Lane Keeping Assist, Active Steering Assist, and Pre-Safe. A fault in the EPS module or Steering Angle Sensor will often disable or degrade these systems simultaneously. On MBUX-equipped vehicles, you may see multiple warnings appear together. All related fault codes should be addressed together, not individually.