Fault code P246B is called “Vehicle Conditions Incorrect for Diesel Particulate Filter (DPF) Regeneration” but in different programs it may be called differently. This fault designation applies to all vehicles equipped with OBD-II.
Technical description and explained code P246B
Fault code P246B is a generic code that is defined as “improper vehicle operating conditions for regeneration of the particulate filter”. It is set on vehicles with diesel engines.
The diesel particulate filter (DPF) is designed to remove ninety percent of the carbon particles (soot) from the exhaust gases of diesel engines. It is located before the catalytic converter or NOx trap.
When engine exhaust passes through the particulate filter, large particles are trapped between the fibers. As soot accumulates, the pressure of the exhaust increases.
After a sufficient amount of soot has accumulated and the exhaust pressure has reached the programmed degree. The filter element must be regenerated to allow the exhaust gases to continue to pass through the DPF.
A special diesel engine fluid is used to convert the remaining exhaust particles to non-toxic exhaust particles. In addition, an elevated temperature is required for complete combustion of the particles in the exhaust system.
Only then is the system able to convert NOx into nitrogen, carbon dioxide and water. To further reduce NOx in the exhaust system, a reductant catalyst (SRC) is added.
The filter must go into regeneration mode for self-cleaning. This only occurs after certain driving conditions have been established. Code P246B is set by the control module when the filter overflows and the required conditions are not met.
When this error occurs, the vehicle sometimes goes into emergency mode, thus limiting engine power and driving speed.
Symptoms of vehicle malfunctions
The main signal that an error P246B has occurred is the Malfunction Indicator Lamp (MIL) is also known as the CheckEngine Light.
It can also be warning signs such as:
- The “Check engine” control lamp on the control panel will illuminate (the code will be stored as a fault).
- The particulate filter control lamp may illuminate.
- Engine power may drop.
- Increased engine temperature.
- Excessive amount of soot emitted with the vehicle exhaust gases.
Error P246B is not considered very serious, however if the problem is not solved for a long time, the engine control module (ECM) can put the vehicle into the emergency mode. This will cause the vehicle speed to be limited and engine power to drop.
Factors that can cause this error code
The error code P246B can mean that one or more of the following problems have occurred:
- Faulty particulate filter.
- DPF pressure sensor is defective.
- Open or short circuit in DPF pressure sensor circuit.
- Use of fuel with high sulfur content.
- Contaminated air filter element.
- Air leak in front of the DPF changes the sensor reading.
- Exhaust leakage.
- Incorrect ECM strategy prevents proper regeneration.
- Sometimes the cause is a faulty ECM module.
How to fix or reset OBD-2 code P246B
Some suggested steps for troubleshooting and fix the error code P246B:
- Connect the OBD-II scanner to the vehicle’s diagnostic connector and read all stored data and error codes.
- Clear the error codes from the computer memory.
- Test-drive the vehicle to see if the error appears again.
- If the code appears again, visually inspect the electrical wires and connectors.
- Check the particulate filter as well as the particulate filter pressure sensor.
- Repair or replace any damaged or defective components.
- Test and replace the engine control module (ECM) if necessary.
Diagnose and repair of problems
It is better to start troubleshooting error P246B with a visual inspection of relevant harnesses and connectors. You should pay special attention to the wiring near the hot exhaust components and sharp edges.
The DPF pressure sensor should then be checked with a multimeter. If the sensor does not meet the manufacturer’s resistance requirements, it should be replaced.
If the sensor is OK, check the hoses for blockages or breaks and clean or replace if necessary. Use high temperature silicone hoses for replacement.
The hoses to the DPF pressure sensor may be melted or cracked from the temperature. Therefore, it may be necessary to reroute them to exclude the high temperature elements when replacing them.
After testing the sensor and inspecting the hoses, check the electrical circuitry of the system. Disconnect all associated control modules before checking the resistance with a multimeter. If necessary, repair or replace damaged or shorted circuits.
By following all recommendations, error P246B will most likely be corrected and will disappear. If it does not, the problem may be a faulty engine control module (ECM).
On which vehicles does this problem occur most frequently
Fault code P246B can occur on different vehicles but there are statistics on which brands this occurs most often. Here is a list of some of them:
- Ford (Kuga, Mondeo, S-Max)
- Land Rover
- Mercedes-Benz
Fault code P246B can sometimes be found with other errors. The most common are the following: P244C, P244D, P244E, P244F, P2458, P2459.
