P128B Mercedes-benz Vision Diagnostic Trouble Code

P128B Mercedes-benz Vision code definition:
P128B is a kind of OBD-II Diagnostic P-Powertrain Diagnostic Trouble Code for Mercedes-benz Vision.

P128B Mercedes-benz Vision 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. If the car doesn't start, they will proceed by testing the voltage at the fuel pump connector and see if the fuel pump relay, fuse, and PCM circuitry should be inspected.

Symptoms

Symptoms of a P128B Mercedes-benz Vision diagnostic trouble code may include:

If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Corroded or damaged connector
Reduction in engine performance, especially at low RPM levels
Malfunction Indicator Lamp (MIL) illuminated

Possible Causes :

Fuel with a large percentage of sulfur will clog the DPF quickly
The Mass Airflow sensor will also cause this problem. Mass Airflow circuit malfunction.
Dirty air cleaner element Damaged DPF

Common Misdiagnoses

TP Sensor Learn Not Complete Problem
Low Coolant Circuit Problem
Cruise Control System - Vehicle Accel Too High Problem
TFP Valve Position Switch-Drive Without Drive Ratio Problem
Problem

Repair Processes :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. If you find a related TSB, the information will often help in diagnosing the code in question as TSBs are crested from many thousands of repairs.

Process Tips

Diagnostic trouble code P128B Mercedes-benz Vision 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 P128B Mercedes-benz Vision.

Fortunately, P128B Mercedes-benz Vision is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.