Guide To P2040 OBD Error Code Solutions

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Wondering on how to solve the error code P2040? Well, Parts Avatar has it all for you! Here’s how you can treat the error code P2040. This code P2040 is a generic OBD-II code that signals at a reduction injection air pressure sensor circuit high input. Although, one should note that the error code P2040 is mostly used by the manufacturers with forethought and they tend to change the usage of the code as per their convenience. Also, this defination isn’t used by most manufacturers (some, like Mercedes use it for another code). According to Mercedes, this code P2040 indicates an issue with the oil quality sensor ME-SFI. When the oil quality signal is improbable or out of the specifications (duty cycle range of smaller than 17% to larger than 83%) while checking the oil dielectric content for excess water in the oil.

It should be noted that whenever there is a problem detected with reductant injection air pressure sensor, the code P2040 is stored. Also, the reductant injection air pressure sensor is a part of the reductant (DEF) system.

What causes this problem with the Reductant Injection Air Pressure Sensor A Circuit High?

• A damaged reductant air pressure sensor (A)
• The reductant injection air pressure sensor system having short circuits
• A malfunctioning SCR controller/PCM or programming error

1. Air pressure sensor - Observing a rich or lean fuel mixture? A rough idle? Yes, all this is caused due to problems in your air pressure sensor. We advise you to get your air pressure sensor changed or repaired as soon as possible from Parts Avatar.
2. SCR controller - An SCR controller is a semiconductor, or integrated circuit (IC) that enables the control of current using a small current. So in order to maintain the proper functioning of the system, it is important to restore or repair your damaged SCR controller immediately. Log into Parts Avatar now!
3. Powertrain control module - A defective powertrain control module can lead to a lot of problems including a poor fuel economy and a diminished engine performance. So if you want to get rid of all these problems, you should change your PCM now.
4. Engine oil - See the oil pressure warning light? Degraded engine gaskets? Well, all this is likely to accompany a low engine oil. Upgrade your engine oil now in order to get away with all these problems now! 
5. Oil filter - Don’t know what a clogged oil filter can do? It can raise issues like excessive mileage and strange noises. We recommend you to get your oil filter changed or repaired immediately.
6. Oil sensor - Is your oil pressure gauge at zero? Oil pressure light blinking? So if you want to save your money from getting wasted on major after repairs, change or repair your oil sensor now!

It is essential 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 P2040 here:

Common Symptoms

• Falling fuel efficiency
• Black smoke emitting from the vehicle exhaust
• Reduced engine performance
• Other codes associated to SCR

Here are some ways with the help of which you will be able to correct the OBD Code P2040

• Replace or repair the hanging oil and filter
• The oil sensor should be mended or restored if the oil quality readings fail to change after the oil and filter have been replaced

There is no need to be anxious as Parts Avatar – Car Parts Online is here to help you out! We have high grade air pressure sensor, SCR controller, PCM, engine oil, oil filter, oil sensor, air pressure sensor and a lot more for our precious customers.

Here are some steps which you should follow in order to diagnose this P2040 fault code:

When you start the procedure, ensure that the reductant/regeneration supply system doesn’t lose pressure both internally or externally. Then the pump should be actuated to create pressure and the system should then be checked for external leaks. A fuel pressure tester should be employed to regulate the reductant system pressure manually. The supply pump and the injector should be checked for leakage. If in case you find leaks (internal or external), they must be mended or restored before continuing with the diagnosis procedure.

All that is required for an accurate diagnosis is a diagnostic scanner, a digital volt/ohmmeter (DVOM) and a source of vehicle specific diagnostic information. The source of vehicle information to should be used to locate a technical service bulletin (TSB) that parallels the vehicle year, make/model; as well as the engine size, code/s stored, and the symptoms displayed. Finding one can help yielding helpful diagnostic information.

The scanner (linked to the vehicle diagnostic connector) should be used to restore all the stored codes and freeze frame data that is relevant. Write this information down before the codes are cleared then perform a test-drive of the vehicle until the PCM either enters readiness mode or the code reappears.

At times, when the powertrain control module enters the readiness mode, the code stored is an intermittent one and may be much more tough to diagnose. In such situations, the conditions that added to the code being stored may need to worsen before a precise diagnosis can be made.

Also, if the code reappears immediately, the next step of your diagnosis requires you to look into the vehicle information source for diagnostic flow-charts, connector pin-out charts, connector face views, and component testing procedures/specifications.

Common Mistakes When Diagnosing The P2040 Code

Here we have listed a few common mistakes that should be avoided:

• A fault in the powertrain control module (PCM)
• Malfunctioning reductant air pressure sensor
• Wiring issues in the system

P2041 - Reductant Injection Air Pressure Sensor "A" Circuit Intermittent