B3959 Diagnostic Trouble Code

B3959 is a kind of OBD-II Diagnostic B-Body 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 B3959 diagnostic trouble code may include:

Poor fuel economy
Possible spark knock (detonation / pre-ignition)
Misfire
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 vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.

Repair Processes :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. 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. If the scan tool has that capability, and the scan tool can operate the IMRC valves, then the problem is either resolved and a simple code clearing is all that's left or a new PCM would be called for.

Process Tips

Diagnostic trouble code B3959 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 B3959.

Fortunately, B3959 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P1205 Trouble Code For Specific Cars

B3959 Skoda Octavia I Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)
B3959 Volvo 940
B3959 Porsche Boxster Type 987 Fuel Pressure Regulator 1 Performance
B3959 Mercedes-benz Cls Class Air Suspension Compressor Relay Circuit Open
B3959 Vegantune Evante PSD Not Fully Closed During Self-Test
B3959 Mg Rv13 Air Temperature Internal Sensor Circuit Open
B3959 Bugatti Type 17 Cylinder #8 High To Low Side Open