P20F2 OBD Error Code: Problem & Solutions

<<See All OBD Codes

The trouble code P20F2 can be explained as SCR NOx Catalyst Efficiency Below Threshold 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. One thing which you must keep in mind that its symptoms as well as causes would surely vary as it depends upon a number of things. The temperature for the selective catalyst reduction system (SCR) system is being monitored by the engine control module. This trouble code would be set by the ECM when the temperature for the selective catalyst reduction system (SCR) system would not be as per the specifications set by the manufacturer.

This trouble code is generic, which would mean that it can apply to all the vehicles which are equipped with the OBD-II or the vehicles which are made since 1996 up to the present. The specifications on the definition, the troubleshooting steps as well as repairs can always vary from one vehicle make to another. This can happen because of a lot of reasons and the mechanic should diagnose the specific cause for this code.

What causes this problem with the SCR NOx Catalyst Efficiency Below Threshold Bank 2?

• Malfunctioning SCR injector
• There can be inoperative O2, NOx, or temperature sensor
• Unusable SCR system
• Imperfect DEF fluid
• Installation of aftermarket or high-performance exhaust components
• Pre-catalyst exhaust might start leaking
• Defective SCR controller or programming error

It is vital to know the symptoms of an issue as only then you would be able to solve the problem. So that’s why we have listed out some major symptoms of OBD Code P20F2 here:

Common Symptoms

• Decrease in the engine performance
• A lot of black smoke from vehicle exhaust
• There might be reduction in fuel efficiency
• Other SCR and emission associated 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:

• Make sure to mend the faulty SCR injector
• Repair or replace the quirky SCR system parts
• Rehabilitate the defaults in the SCR controller or programming error
• The malfunctioning electronic control unit should be repaired or replaced as per the need
• Carefully adjust the faults in the exhaust temperature sensor
• Recondition the non-functioning PCM/ECM

Parts Avatar Canada endeavour’s to fulfil all the needs of its consumer, that’s why we have a huge collection of top quality Nox sensor, ecm, pcm, exhaust temperature sensor, oxygen sensor, ecm car, pcm car and many more at equitable prices. We won’t let you down in any way.

Here are some steps which you should follow in order to diagnose this fault code:

As an initial step the mechanic will carefully inspect the vehicle with the help of a scanner. After this, the technician will connect a scanner to the diagnostic code so that he can recover all the codes and freeze frame data. Note down this information as it can clearly help for further diagnosis. After careful inspection, he will reset the code and test drive your vehicle to check for reappearance of the codes. 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 P20F2. 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 P20F2 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 P20F2 Code

• Non performance of the DEF injector

• Failure in the DEF
• Defaults in the selective catalytic reduction