U0928 Mercedes-benz 560 Diagnostic Trouble Code

U0928 Mercedes-benz 560 code definition:
U0928 is a kind of OBD-II Diagnostic U-Network Diagnostic Trouble Code for Mercedes-benz 560.

U0928 Mercedes-benz 560 is defined as Knock Sensor Circuit Range Performance (Bank 1 or Single Sensor). This refers to camshaft timing, which in this case is over-retarded. This is because the barometric pressure sensor is part of the MAF sensor. Sometimes, the MAF's sensing wire can accumulate and get covered with dirt, dust and/or oil residue, which can also lead to the error code.

Symptoms

Symptoms of a U0928 Mercedes-benz 560 diagnostic trouble code may include:

The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Faulty PCM
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Diminished fuel efficiency

Possible Causes :

Faulty IMRC actuator/sensor
A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.
An air leak forward of the DPF will change the sensor readings resulting in the code

Common Misdiagnoses

Vehicle Speed Output Circuit Problem
Cruise Control Servo Indicates Low Problem
A/C System High Pressure High Temperature Problem
PCM Stack Overrun Problem
Transmission Control Module Reprogrammable Memory Problem

Repair Processes :

Once located, visually inspect the connectors and wiring. Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors. Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness.

Process Tips

Diagnostic trouble code U0928 Mercedes-benz 560 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 U0928 Mercedes-benz 560.

Fortunately, U0928 Mercedes-benz 560 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.