B0239 Land Rover Defender is described as Fuel System Too Rich, which basically means bank 1's oxygen sensor has detected a rich condition of fuel. This means there's not enough oxygen in the exhaust from too much fuel being delivered into the air and gas mixture for combusion. This is because the barometric pressure sensor is part of the MAF sensor. Sometimes, the MAF's sensing wire can accumulate and get covered with dirt, dust and/or oil residue, which can also lead to the error code.
SymptomsSymptoms of a B0239 Land Rover Defender diagnostic trouble code may include:
Possible Causes :
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. You might continue by connecting the scanner to the vehicle diagnostic connector and retrieving all stored codes and freeze frame data. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.
Diagnostic trouble code B0239 Land Rover Defender 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 B0239 Land Rover Defender.
Fortunately, B0239 Land Rover Defender is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.