Mercedes S 350 P0957 Engine Trouble Code
What is Mercedes S 350 P0957?
When Mercedes S 350 P0957 code appears, first check your gas cap. Pull over safely, ensure it is tight, and inspect for cracks. A loose or damaged gas cap affects fuel-system pressure and emissions. A replacement cap costs about $3–$10. This simple fix can resolve the code and improve fuel economy.
P0957 on the Mercedes S 350
The Mercedes S 350 ECU flash version prior to the 2.4.1 update has a known calibration bug that can generate spurious P0957 codes under hard deceleration. Verifying the ECU software version is always the first step before any mechanical diagnosis on this model.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Mercedes S 350 |
| Brand: | Mercedes |
| Model: | S 350 |
| Code: | P0957 |
P0957 Mercedes S 350 Symptoms
Check Engine Light
Illuminated Mercedes S 350 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Mercedes S 350
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Mercedes S 350
Increased Emissions
Failed emissions test due to P0957
P0957 Code Structure
Understanding what each digit means in the P0957 powertrain trouble code:
| P | 0 | 9 | 5 | 7 |
|---|---|---|---|---|
| Powertrain Code | Intake Valve Control Solenoid Circuit Low | Injector Circuit Malfunction - Cylinders | Cylinder 1 Injector Circuit Low | Shift/Timing Solenoid Malfunction |
How to Fix Mercedes S 350 P0957
Diagnostic Steps:
Oxygen sensors measure exhaust gas oxygen content to optimise air-fuel ratio. This optimisation improves fuel economy and reduces emissions. Sensors degrade over time and require periodic replacement.
Repair Solution:
Crankshaft position sensor signals the computer for precise ignition and fuel injection timing. Faulty sensors cause rough running and reduced efficiency. Modern vehicles enter limp mode and illuminate the check-engine light.
Technical Notes:
Parts or components should not be replaced based solely on P0957 DTC. Consult your vehicle service manual for proper diagnostic procedures, possible causes, and required testing before replacement.
Mercedes S 350 P0957 Repair Cost
A complete diagnostic health-check on the Mercedes S 350 before committing to any single repair costs $120–$180 at a dealership with live-data capability. This investment pays for itself if it prevents unnecessary part replacement, which is the single most common mistake when diagnosing P0957.
P0957 Description
P0957 engine trouble code is related to Shift/Timing Solenoid Malfunction.
Main Cause
The primary reason for P0957 OBD-II Engine Trouble Code is: Injector Circuit Malfunction - Cylinders.
Common P0957 Misdiagnosis on the Mercedes S 350
A common error on the Mercedes S 350 is attributing P0957 to the crankshaft position sensor when the real fault is a damaged flywheel ring gear. The missing tooth pattern created by ring gear damage is intermittent and generates the same signal anomaly.
DIY Repair Guide: P0957 on Mercedes S 350
For Mercedes S 350 owners without a scan tool, a free diagnostic check is available at most franchised Mercedes dealers during a courtesy health-check appointment. This provides the DTC number needed to research the exact cause of P0957 before committing to any repair.
Preventing P0957 on the Mercedes S 350
For turbocharged Mercedes S 350 models, allowing the engine to idle for 60–90 seconds before shutdown after hard driving reduces turbocharger heat soak and prevents the coking of oil that blocks VVT galleries — a known secondary trigger of P0957.
Frequently Asked Questions — Mercedes S 350 P0957
A: Contaminated or low-octane fuel can temporarily trigger P0957 through knock retard and lean/rich excursion events. If the code appeared shortly after a fill-up at an unfamiliar station, running the tank close to empty and refuelling with premium is a sensible first step.