P0172 on Mercedes-Benz E-Class: Fix & DLC Location
Factory diagnostic troubleshooting wire for fault code P0172 (System Too Rich (Bank 1) - Symptoms, Causes & Step-by-Step Fix) specifically on the Mercedes-Benz E-Class (2020–2026, 2.0L Turbo 4-Cyl (E 350) / 3.0L Turbo Inline-6 (M256 E 450 375HP)).
1. Symptoms of P0172 on Mercedes-Benz E-Class
When the Engine Control Module (ECM/PCM) on your Mercedes-Benz E-Class (2.0L Turbo 4-Cyl (E 350) / 3.0L Turbo Inline-6 (M256 E 450 375HP)) logs fault code P0172, drivers commonly observe:
2. Most Likely Causes on Mercedes-Benz E-Class
Historical warranty claims and technical repair bulletins for Mercedes-Benz E-Class point to the following failure distribution:
3. Step-by-Step DIY Repair Guide for Mercedes-Benz E-Class
Use dedicated MAF cleaner to remove carbon buildup from sensor wires. on the Mercedes-Benz E-Class equipped with 2.0L Turbo 4-Cyl (E 350) / 3.0L Turbo Inline-6 (M256 E 450 375HP).
Use live OBD-II scanner data; negative trims beyond -10% indicate the ECU is cutting fuel. on the Mercedes-Benz E-Class equipped with 2.0L Turbo 4-Cyl (E 350) / 3.0L Turbo Inline-6 (M256 E 450 375HP).
Perform a fuel pressure leak-down test to identify injectors leaking raw gasoline into cylinders while parked. on the Mercedes-Benz E-Class equipped with 2.0L Turbo 4-Cyl (E 350) / 3.0L Turbo Inline-6 (M256 E 450 375HP).
Other Common Fault Codes on Mercedes-Benz E-Class
Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Mercedes-Benz E-Class:
4. Mercedes-Benz E-Class P0172 FAQs
What causes code P0172 to trigger on a Mercedes-Benz E-Class?
On the Mercedes-Benz E-Class (2.0L Turbo 4-Cyl (E 350) / 3.0L Turbo Inline-6 (M256 E 450 375HP)), P0172 is most frequently caused by Faulty or leaking fuel injector or Contaminated Mass Air Flow (MAF) sensor.
Where is the OBD-II port located on my Mercedes-Benz E-Class?
On the Mercedes-Benz E-Class, the 16-pin DLC diagnostic connector is located Under driver dashboard behind safety clip bezel. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.
Can I safely drive my Mercedes-Benz E-Class with code P0172?
Driveable short distances, but unburnt fuel can damage catalytic converters. Given that P0172 carries a Medium severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.