P209D - OBD Trouble Code

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Is the car engine not performing at par with the expectations? Do you notice affected fuel economy, increased emissions from the tailpipe and Check Engine Light illuminated on the dashboard? This can be an indication of the problem with the air injection pressure sensor of the vehicle, resulting in OBD code P209D getting stored in the Powertrain Control Module (PCM).

Whenever the PCM finds that the output voltage from the reductant injection air pressure sensor B circuit is higher that the specification, the OBD code P209D gets stored in the system. The PCM regularly monitors the supply pump fluctuations and load percentage to determine the optimal working condition and illuminated the check engine light, whenever any error code is found.

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

• Defective reductant injection air pressure sensor
• Broken, short or corroded wiring to the sensor circuits
• Poor electrical connections to the sensor circuit
• SCR controller programming error
• PCM failure

1. Engine Control Module – ECM faults are rare but can be a big problem as faulty ECM will cause wrong vehicle operations and can also result in wrong OBD codes getting stored in the system which can also cause misdiagnosis. Thus, replace faulty ECM components now!
2. Powertrain Control Module – Check for PCM error which might be due to circuit faults that might require complete replacement and reprogramming. Replace it now!
3. Diagnostic Tools – Buy quality diagnostic tools to check and diagnose OBD code P209D error with the help of experienced mechanic. Visit us today!
4. Exhaust Gas Recirculation Valve – Bad EGR valve can cause many performance issues. Common signs include engine performance issues like decreased power and acceleration, rough idle, and the Check Engine Light coming on. Thus, replace faulty EGR valve now!
5. 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.

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 P209D here:

Common Symptoms

• Reduced fuel economy
• Increased exhaust emissions
• Degrading engine performance
• CEL (Check Engine Light) illuminated
• Engine performing abnormally
• Excessive exhaust smoke on load

Want to correct the Trouble Code P209D? Read these points mentioned below:

• Reductant injection air pressure sensor replacement
• Diesel exhaust fluid (DEF) pump replacement
• EGR valve replacement
• SCR controller reprogramming
• PCM repair and reprogramming
• Faulty wiring and harness repair or replacement

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Here are some steps which you should follow in order to diagnose this P209D fault code:

• Check for SCR controller and DEF related code error that might also get stored in the PCM along with this code, which can solve the problem easily.
• Inspect the air injector sensor and DEF pump area for any corrosion or leakages on the exterior and if found, suspect it to be failed.
• One will require tools like a diagnostic scanner, digital volt/ohmmeter, and automotive stethoscope.
• Connect the OBD scanner and retrieve all the coded and freeze frame the data. After doing that test run the vehicle again under same circumstances to see if the code returns to make sure which codes are persistent (in case of more than one code).
• Check for damaged, broken and corroded wiring and connector to the sensor circuit and replace them, if required.
• Use the DVOM to test for voltage from the injector pump and check for fluctuations. If the readings are not under specified range, suspect for pump failure and replace it immediately.
• If everything seems to work fine, then check for faulty PCM and replace or reprogram as required.

Common Mistakes When Diagnosing The P209D Code

It is important to understand that there can be many other factors causing this problem rather than directly blaming the injection system completely. Always check for faulty wirings, and fuses as well as air injector sensor and DEF parts for error too. Take help of professional mechanic to solve OBD code problem as this will ensure avoidance of misdiagnosis and can also help to reduce the costs associated with the repairs.

• Reductant air injector pressure sensor failure
• Powertrain Control Module (PCM) failure
• Wiring and connector issues in relation to the sensor and circuits
• Damaged or clogged DEF pump