P1931 Diagnostic Trouble Code

P1931 is a kind of OBD-II Diagnostic P-Powertrain 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 P1931 diagnostic trouble code may include:

Possible spark knock (detonation / pre-ignition)
Poor fuel economy
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
Hesitation upon acceleration

Possible Causes :

A plugged converter will cause of host of driveability problems as well as set this code. A severely plugged converter will result in the inability to increase rpm when under load. Look for a code such as P0421 -- catalytic converter efficiency below threshold if the converter indicating a faulty converter.
Dirty air cleaner element Damaged DPF
Defective ECU strategies or components will prevent proper regeneration

Repair Processes :

You might continue by connecting the scanner to the vehicle diagnostic connector and retrieving all stored codes and freeze frame data. If the engine displays a miss and there wasn't a code, determine which cylinder is misfiring. If the exhaust manifold is visible, spay or pour a small amount of water on each cylinder exhaust port. Water will evaporate immediately on good cylinders and slowly on the missing cylinder. If this can't be accomplished pull the plugs and check the condition. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.

Process Tips

Diagnostic trouble code P1931 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 P1931.

Fortunately, P1931 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P1931 Trouble Code For Specific Cars

P1931 Mitsubishi Raider Aux Heater Flame Out Fault
P1931 Toyota Starlet Passenger Door Ajar Circuit Short To Ground
P1931 Lada 2105 Shift Solenoid A Electrical/1-2 Shift Solenoid Circuit Electrical
P1931 Bmw 330 Child Seat Detection Circuit Open
P1931 Lotus 72 Torque Converter/Brake Switch B Circuit High
P1931 Darracq 3-litre Heated Catalyst Efficiency Below Threshold (Bank 2)
P1931 Volkswagen Vento SCP (J1850) Invalid or Missing Data for Cassette Tape