B0859 Diagnostic Trouble Code

B0859 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 B0859 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. Look at the plug wires to make sure they are not burnt or laying on the exhaust. Once located, visually inspect the connectors and wiring. Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors.

Process Tips

Diagnostic trouble code B0859 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 B0859.

Fortunately, B0859 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

B0859 Trouble Code For Specific Cars

B0859 Dacia Sandero Ii Fuel Temperature Sensor B Circuit Intermittent
B0859 Toyota Fchv O2 Sensor Signals Swapped Bank 1 Sensor 2/ Bank 2 Sensor 2
B0859 Rolls-royce Legalimit Hydraulic Pump Relay Circuit Failure
B0859 Toyota Rav4 Park Brake Valve Solenoid #1 Sense Input Circuit Failure
B0859 Mercury Monarch Air Suspension Rear Height Sensor High (SE) Signal Circuit Short To Ground
B0859 Subaru Sagres Liftgate Disarm Switch Circuit Short to Ground
B0859 Mg M-type Air Suspension Warning Lamp Circuit Open