🔍 What the P047214 Code Means

Fault code P047214 indicates an electrical short circuit in the Exhaust Back Pressure Sensor 1. This sensor monitors the exhaust pressure to help control turbocharger operation and exhaust gas recirculation (EGR) efficiency. When the ECM (Engine Control Module) detects an irregular signal—often due to a shorted circuit, damaged wiring, or sensor contamination—it triggers this code and illuminates the Check Engine Light.

🧭 Sensor Location on the Mercedes 2.1 Diesel

On most OM651 Mercedes engines (found in GLA, E-Class, C-Class, Sprinter, and others), the Exhaust Back Pressure Sensor sits near the rear of the engine block, connected to a small metal pressure pipe coming from the exhaust manifold. Removing the top engine cover reveals it clearly—it’s a small sensor with a single electrical connector and a short metal tube fitting underneath.

Tip from the mechanic in the video: "90% of the time it’s this sensor, but sometimes it’s just clogged with soot, not electrically bad."

⚙️ Common Causes of P047214

• Heavily soot-clogged exhaust back pressure pipe
• Sensor internal short circuit due to heat or oil contamination
• Damaged wiring harness near the turbocharger area
• Moisture or corrosion in the electrical connector
• Use of aftermarket non-OEM sensors

🧽 How to Fix or Clean the Sensor

1. Remove the engine cover to access the sensor.
2. Disconnect the electrical connector carefully.
3. Unscrew the sensor using a suitable socket or wrench.
4. Inspect the sensor port and metal pipe—if clogged, clean with a suitable carbon or DPF cleaner.
5. Reinstall using an OEM or genuine sensor (avoid cheap aftermarket versions).
6. Clear the fault code and check live sensor readings using a professional scanner.

The KOL recommends using genuine parts and avoiding cheap sensors that often fail again within months.

🔧 Best Diagnostic Tool for Mercedes Diesel Systems

After replacing or cleaning the sensor, use a professional diagnostic tool to read and clear DTCs, verify live pressure values, and ensure no wiring faults remain. We recommend the iCarsoft CR Ultra P — a Mercedes-compatible OBD-II scanner that supports:

• Real-time exhaust pressure and EGR system monitoring
• Sensor voltage and short circuit test modes
• Service resets and adaptation functions
• Full-system diagnostics (engine, DPF, SCR, transmission, etc.)

➡️ View iCarsoft CR Ultra P for Mercedes diagnostics

📈 Quick Reset Steps

1. Connect the CR Ultra scanner to the OBD-II port.
2. Select “Mercedes-Benz” → “Engine Control Module.”
3. Read and confirm code P047214.
4. After cleaning or replacing the sensor, choose “Clear Fault Codes.”
5. Start the engine and verify the code does not return under load.

Note: Adaption resets are usually not required for this code.

📚 Related Faults