B3746 Mercedes C 220 Diagnostic Trouble Code

B3746 Mercedes C 220 code definition:
B3746 is a kind of OBD-II Diagnostic B-Body Diagnostic Trouble Code for Mercedes C 220.

B3746 Mercedes C 220 is described as Fuel Rail Pressure Sensor Circuit Malfunction. This code is strictly about the incoming signal from the FRP (fuel rail pressure) sensor falling below the calibrated limit for a certain period of time. Any code that causes the vehicle's engine to die while running should be fixed as soon as possible, as it can be dangerous for both the vehicle and the passengers of the vehicle.

Symptoms

Symptoms of a B3746 Mercedes C 220 diagnostic trouble code may include:

Blown fuse (if applicable)
Engine surge
Reduction in engine performance, especially at low RPM levels
The engine oil will exhibit dilution from the ECUs attempts to increase engine temperature. Some vehicles advance the fuel injection timing slightly after top center to afterburn a small amount of fuel to increase exhaust temperatures. Some of this fuel enters the crankcase. When the ECU determines the necessity to regenerate the DPF, the service life of the oil be shortened significantly

Possible Causes :

Defective ECU strategies or components will prevent proper regeneration
The Mass Airflow sensor is a hot wire that senses the volume of air entering the intake manifold. The computer uses this information to control fuel mixture.
Dirty air cleaner element Damaged DPF

Common Misdiagnoses

Control Module Throttle Actuator Position Performance Problem
Air Conditioning (A/C) Clutch Feedback Circuit High Voltage Problem
Cruise Vehicle Speed/Set Speed Difference Too High Problem
Kick-Down Switch Failed Short Problem
Park/Neutral Postion (PNP) Switch Circuit Engine Torque Signal Circuit Problem

Repair Processes :

With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground. Now, clear the codes and test-drive the vehicle to see if the code is reset. Replace the oxygen sensor that is downstream from the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if a oxygen sensor code stating "heater circuit malfunction" the sensor has most probably failed.

Process Tips

Diagnostic trouble code B3746 Mercedes C 220 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before B3746 Mercedes C 220.

Fortunately, B3746 Mercedes C 220 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.