P01C4 Mercedes Cl 500 Diagnostic Trouble Code

P01C4 Mercedes Cl 500 code definition:
P01C4 is a kind of OBD-II Diagnostic P-Powertrain Diagnostic Trouble Code for Mercedes Cl 500.

P01C4 Mercedes Cl 500 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. So if the problem persists despite of your diagnosis, then you should never hesitate to take your vehicle to your dealer or to a qualified mechanic.

Symptoms

Symptoms of a P01C4 Mercedes Cl 500 diagnostic trouble code may include:

Excessive exhaust leak
Hesitation upon acceleration
Malfunction Indicator Lamp (MIL) illuminated
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected

Possible Causes :

A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
Faulty IMRC actuator relay (if equipped)
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.

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 :

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. 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.

Process Tips

Diagnostic trouble code P01C4 Mercedes Cl 500 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 P01C4 Mercedes Cl 500.

Fortunately, P01C4 Mercedes Cl 500 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.