U103C Diagnostic Trouble Code

U103C is a kind of OBD-II Diagnostic U-Network Diagnostic Trouble Code.

It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.

Symptoms

Symptoms of a U103C diagnostic trouble code may include:

Faulty PCM
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Poor acceleration
Rich or lean exhaust

Possible Causes :

The Mass Airflow sensor will also cause this problem. Mass Airflow circuit malfunction.
Fuel with a large percentage of sulfur will clog the DPF quickly
A large air leak at or near the number one oxygen sensor would also cause a lean mixture.

Repair Processes :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem.

Process Tips

Diagnostic trouble code U103C 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 U103C.

Fortunately, U103C is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U103C Trouble Code For Specific Cars

U103C Mercedes Gl Accelerometer Rear Circuit Failure
U103C Mercury Monterey Air Suspension Rear Height Sensor Low Signal Circuit Short To Battery
U103C Innocenti Mini
U103C Citroen Rally Raid Fuel Pump Secondary Circuit Intermittent
U103C Bentley Continental Gt Battery Power Supply ECU Circuit Short To Ground
U103C Mercedes Sl 65 Air Bag Crash Sensor #2 Ground Circuit Short To Battery
U103C Alvis Speed Air Flow Blend Door Driver Circuit Failure