C1901 Diagnostic Trouble Code

C1901 is a kind of OBD-II Diagnostic C-Chassis 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 C1901 diagnostic trouble code may include:

Diminished fuel efficiency
Fuel pressure too high
Malfunction Indicator Lamp (MIL) illuminated
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 :

A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.
Faulty IMRC actuator/sensor
Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)

Repair Processes :

You might continue by connecting the scanner to the vehicle diagnostic connector and retrieving all stored codes and freeze frame data. 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 C1901 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 C1901.

Fortunately, C1901 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C1901 Trouble Code For Specific Cars

C1901 Royce 10 Hp Ignition Key-In Circuit Short To Ground
C1901 Volkswagen Passat Right Rear Stop lamp Circuit Failure
C1901 Healey Silverstone Passenger's Front Seat Up Switch Circuit Short to Battery
C1901 Volkswagen Transporter
C1901 Jaguar X-type Seat Driver Rear Down Circuit Short To Ground
C1901 Subaru B9 Left Front Center Sensor Circuit Failure
C1901 Volvo S40