P20F0 - OBD Trouble Code

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The trouble code P20F0 can be explained as SCR NOx Catalyst - Over Temperature Bank 2. This diagnostic fault code is a generic powertrain code, which means that it would apply to the OBD-II equipped vehicles. The specific repair steps can vary as it depends upon the vehicle make and model. The engine control module, powertrain control module or the transmission control module monitors this circuit depending upon the particular automobile. The selective catalyst reduction (SCR) catalyst is examined to ensure it is capable of NOx conversion. The concentration of NOx upstream of the SCR is calculated depending upon the automobile’s model. It is the NOx sensor which measures the NOx concentration downstream of the SCR. These concentrations are then used to calculate the cumulative efficiency of the SCR catalyst and it is then compared to a threshold.

If the engine control module would detect a variation in the voltage coming from the temperature for the selective catalyst reduction system (SCR) system that is outside the parameters set by the automobile manufacturer, then it would store the P20F0 error code. This would also give rise to the illumination of the check engine light.

What causes this problem with the SCR NOx Catalyst - Over Temperature Bank 2?

• Faulty exhaust temperature sensor
• Malfunctioning SCR system
• There can be inoperative SCR injector
• DEF fluid might not be sufficient enough
• Some issues related to the SCR controller or programming error
• Unusable pre-catalyst exhaust
• Installation of aftermarket or high-performance exhaust constituents

1. Diesel Exhaust Fluid Pump – If the DEF pump will not function properly, it can cause increased emissions in the exhaust system and reduced the longevity of the filtration elements in the exhaust system. Thus, replace faulty pump immediately.
2. Engine Control Module - If there is any corrosion or breaks in the internal wiring of the harness, then it can cause a short in the ECM or can also cause corrosion in the ECM through the wiring harness. You can always rely on us as we have best auto parts for our customers.
3. Powertrain Control Module - The onboard computer, or powertrain control module is the brain of the engine control system. Now if the brain is not working properly, then neither is the car engine. Get it replaced before the situation gets worse.
4. Diesel Exhaust Fluid Heater – If the diesel exhaust fluid heater is faulty, it will not be able to aid in conversion of harmful nitrous oxide compounds to nitrogen, carbon dioxide and water vapours to control emissions. Thus, replace it immediately.
5. Electronic Control Unit - Is your car jump starting on reverse polarity? Or are you facing some intermittent starting issues? If yes, then it indicates that your electronic control unit is bad. So it is very important to replace the defective electronic control unit with us at equitable prices.
6. Diagnostic Tools - Buy quality diagnostic tools to check and diagnose OBD code P20F0 error with the help of experienced mechanic. Visit us today!

There could be countless symptoms which that would accompany with this fault code. Willing to know some common symptoms of OBD Trouble Code P20F0? Your wish is our demand. Have a look at them below:

Common Symptoms

• The engine performance might be reduced
• Diminishing fuel mileage
• Excessive black smoke might start emitting from automobile exhaust
• There might be some other SCR and emission related codes

Looking out for some ways with the help of which you can correct this fault code? Then you have arrived at the correct place. We are here to help you out, so you must check out the steps mentioned below as follows:

• You must fix the defective PCM/ECM
• Make sure to mend the faulty SCR system parts
• It is essential to restore the flawed SCR injector
• Repair or replace the quirky exhaust temperature sensor
• Rehabilitate the defaults in the SCR controller or programming error
• Carefully adjust the faults in the electronic control unit

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It is essential to diagnose this fault code. Here are some steps which a mechanic should follow for diagnosing the problem that triggered a P20F0 code to be stored:

• If you find out that other SCR or exhaust emissions codes or exhaust temperature codes are stored, then make sure to address them before attempting to diagnose the stored P20F0.
• Repair any pre-catalyst leakages in the exhaust before attempting a diagnosis for this type of fault code.
• It is essential to have a diagnostic scanner, a digital volt/ohmmeter (DVOM), an infrared thermometer with a laser pointer, and a source of vehicle specific SCR system diagnostic information to easily diagnose the P20F0 fault code.
• Carefully locate the technical service bulletin (TSB) which would match the vehicle year, make, and model; as well as the engine size, code/s stored, and symptoms exhibited could yield helpful diagnostic information.
• A visual inspection of the SCR injection system, exhaust temperature sensors, NOx sensors, and oxygen (02) sensor harnesses and connectors should be done before starting the process of diagnosis. Make sure to repair or restore the burnt or faulty wiring and or connectors before proceeding.
• Then the next step would be to locate the vehicle diagnostic connector and plugging in the scanner. All stored codes should be retrieved and pertinent freeze frame data and record this information before clearing the codes.
• Then the vehicle should be taken out for a test drive until the powertrain control module would enter the readiness mode or the code is reset.
• Now if the PCM does enter readiness mode, this would mean that the code is intermittent and may be much more difficult to diagnose at this time.
• The conditions which contributed to the code being stored should be allowed to worsen before a diagnosis can be reached.
• Once the code has been reset immediately, search your source of vehicle information to get diagnostic flow charts, connector pin out charts, connector face views, along with constituent testing procedures as well as specifications.
• This information would prove to be very helpful in completing the next steps of your diagnosis.
• Carefully observe the scanner data stream to compare exhaust (pre-cat and post-cat) temperature sensor data between engine banks.
• If it detects some inconsistencies, then the exhaust temperature sensors should be tested using the DVOM. If the sensors would fail to comply with the specifications set by the manufacturer, then it would indicate that it is faulty.
• Now if all sensors and circuitry appear to be functioning as intended, then it would mean that the catalyst element is defective or there is a failure in the SCR system.

Common Mistakes When Diagnosing The P20F0 Code

• Some issues related to DEF contamination
• There can be a failure in the DEF injector
• Selective catalytic reduction problems