C1921 Diagnostic Trouble Code

C1921 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 C1921 diagnostic trouble code may include:

Reduction in engine performance, especially at low RPM levels
Vacuum leak on the engine
Diminished fuel efficiency
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.

Possible Causes :

Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
Dirty air cleaner element Damaged DPF

Repair Processes :

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

Process Tips

Diagnostic trouble code C1921 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 C1921.

Fortunately, C1921 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C1921 Trouble Code For Specific Cars

C1921 Lada 1300 Shift Malfunction
C1921 Belsize 12 Bank 2 Fuel Control Shifted Rich
C1921 Bentley Azure Battery Power Supply ECU Circuit Failure
C1921 Lti Fx Traction Control System Malfunction
C1921 Isuzu Rodeo SCP (J1850) Invalid or Missing Data for Vehicle Id (VIN)
C1921 Case Jic Door Ajar Lamp Circuit Failure
C1921 Mercedes-benz 170 Air Bag Internal Diagnostic Monitor Fault or System Disarm Fault