B2859 Diagnostic Trouble Code

B2859 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 B2859 diagnostic trouble code may include:

Faulty PCM
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Poor acceleration
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
A large air leak at or near the number one oxygen sensor would also cause a lean mixture.

Repair Processes :

Replace the oxygen sensor that is downstream from the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if a oxygen sensor code stating "heater circuit malfunction" the sensor has most probably failed. Once located, visually inspect the connectors and wiring. Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors. 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 B2859 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 B2859.

Fortunately, B2859 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

B2859 Trouble Code For Specific Cars

B2859 Lagonda 3.5-litre Shift Solenoid D Intermittent
B2859 Morgan 4 Booster Pedal Force switch circuit Failure
B2859 Land Rover Discovery 2 Steering Column Switch Circuit Short to Battery
B2859 Iso Grifo SCP (J1850) Invalid or Missing Data for Primary Id / Vehicle Speed
B2859 Trident Clipper Passenger Side Crash Sensor Internal Fault
B2859 Chevrolet Model EGI Mini - MAF Failed Open Circuit
B2859 Perodua Kancil Driver's Seat Seatback Autoglide Rearward Switch Circuit Short to Ground