P2BAC - OBD Trouble Code

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Is your car having an affected performance issue? Is there black smoke emitting from the car exhaust? Is there a sudden drop in the fuel economy? All these are the indications to the OBD Code P2BAC being stored and flashed in the Powertrain Control Module (PCM).

The Exhaust Gas Recirculation system recirculates a part of the exhaust gas back into the engine cylinders through the combustion chamber. The exhaust gas is hotter than the fresh air which gets sucked by the engine. Thus, the exhaust gas aids in significantly reducing the contents of the cylinder for combustion. Because of non-presence of oxygen (O2), the exhaust gases can’t burn, since they contain neither fuel nor oxygen particles.

Thus, it results in lower heat discharge and cylinder temperatures. It reduces the formation of nitrogen oxide (NO2) as well. The inactive exhaust gas which is present in the cylinder limits the peak temperatures. It also decreases the loss due to throttling in petrol engines while improving the engine life by reducing the cylinder temperatures. The three-stage catalytic converter further reduces the NOx to acceptable levels.

What causes this problem with the NOx Exceedance - Deactivation of EGR?

• Faulty, damaged or dirty MAP sensor
• Open or short in the NOx sensor circuit
• Ground circuit open or shorted
• Faulty PCM that might require reprogramming
• Faulty EGR valve
• Poor connections to the EGR system circuit
• There might be a cat back exhaust system without EGT provisions installed

1. Electronic Control Unit - ECU monitors the temperature differences in the boost converter with the help of the temperature sensors to prevent the converter from overheating and malfunctioning. Thus, replace faulty ECU immediately.
2. Automatic Transmission Module - Sometimes the automatic transmission module is unable to communicate or correctly anticipate the speed of the vehicle and thus creates difficulty in gear shift leading to sluggish acceleration, throttle response and stalling. Thus, can also hamper a lot of components physically and thus must be checked and replaced, if required.
3. Engine Control Module - ECM failures and faults can be very difficult to find and resolve as these are very rare and might require a complete reprogramming of the system to avoid wrong codes from getting stored in the system, leading to misdiagnosis. Replace it now!
4. Powertrain Control Module - Faulty PCM can disrupt the normal functioning of the vehicle by affecting the transmission system and the fuel delivery system. This will cause the system to store wrong OBD error and thus can lead to misdiagnosis.
5. Oxygen Sensor - If the fuel to air ratio is not correct, the engine may work in lean or rich conditions. This not only hampers the performance output, but also affects the fuel economy, exhaust emissions and acceleration. Thus, a faulty oxygen sensor must be replaced as if it important for keeping in check the oxygen levels entering/exiting the engine.
6. Exhaust Gas Recirculation Valve - It is auto part commonly found on many road going automobiles. It is a part of the vehicle’s exhaust gas recirculation (EGR) system, an emissions system that is designed to recirculate exhaust gases back into the vehicle’s intake so that it can reduce cylinder temperatures and NOx emissions. Purchase top notch exhaust gas recirculation valve from us at economical prices.
7. Diagnostic Tool - In order to be that DIY guy, you need few diagnostic tools to get your car problems pointed out easily. Our diagnostic tools collection will come in handy to do so, so why not have a look?
8. Diesel Exhaust Fluid Pump - For the proper functioning of the transmission system, the diesel exhaust fluid pump needs to work properly. If it is not functioning, the transmission may slip and cause harsh shifts too. Thus, replace faulty pump now and buy a new one from us!
9. Fuel Injector - The fuel injector is responsible for maintaining optimal levels of the air to fuel ratios in the combustion chambers for the maximum out from the engines. It the fuel injector goes down; it hampers the entire efficiency of the engine. Thus, check and replace the bad injector now!
10. Diesel Exhaust Fluid Pump - If the DEF pump is not functioning properly, the exhaust system will not be able to properly manage the harmful emissions from the vehicle and can also result in inefficient fuel consumption. Thus, replace it now, if found defective.

Our main motive is to achieve customer satisfaction and that’s why we will help you to diagnose P2BAC code by mentioning some major symptoms below:

Common Symptoms

• Check Engine Light flashing in the display monitor
• ECM indicating the stored error code
• Exponential increase in the fuel consumption pattern
• Rough engine with occasional stalling
• Lack of power and acceleration due to failure of fuel delivery system
• Black or white smoke coming from the tailpipe

Have a look at some ways with which you can correct the P2BAC code:

• It is essential to restore the flawed NOx sensor
• Repair or replace the quirky powertrain control module
• Rehabilitate the defaults in the NOx sensor heater control circuit
• Carefully adjust the faults in the SCR controller
• Replacement of faulty EGR valve
• Recondition the non-functioning PCM or programming error

Don’t get tensed if you are still facing any of these issues as we care for our customers and that’s why we offer a good range of DPF, NOx Sensor, O2 Sensor, ECM, PCM and a lot more. We are sure that now all your issues would be resolved.

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

A diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle specific diagnostic information will be required to diagnose a code P2BAC. Locating a technical service bulletins (TSB) that matches the vehicle year, make, and model; as well as the engine size, code/s stored, and symptoms exhibited, could yield helpful diagnostic information.

Begin my diagnosis with a visual inspection of the NOx sensor circuit wiring harnesses and connectors. Repair or replace burnt or damaged wiring and or connectors before proceeding.

Plug the scanner into the vehicle diagnostic connector and retrieve all stored codes and pertinent freeze frame data. Note down this information before clearing the codes.

Next step is to test drive the vehicle until the PCM either enters readiness mode or the code is reset. If the PCM enters readiness mode, the code is intermittent and is more difficult to diagnose.

If the code gets reset immediately, search for your vehicle information source to get diagnostic flow charts, connector pin-out charts, connector face views, as well as component testing procedures and specifications.

Use the DVOM to test (voltage drop) on all NOx control system grounds. Continue by testing the power supply to the NOx control system. Check for the faulty fuses and replace to avoid misdiagnosis.

If the relay has an input voltage but output voltage is absent, suspect that the relay is bad. If the NOx sensor voltage output circuit is within parameters, use the DVOM to test the fuel pressure sensor and fuel pump. If any of these components fails to meet manufacturer’s specifications, suspect that it has failed.

Also inspect for EGT sensor and EGR valve for errors and replace the faulty components immediately.

Common Mistakes When Diagnosing the P2BAC Code

• Diagnostic errors usually occur due to not following the procedure properly. Always follow the test procedure in the diagnosis to ensure there is the correct voltage to the sensor and from the sensor to the ECU.
• Many a time the mechanic might not remove the EGT sensor and forget to inspect for excessive soot or ash on the sensor.
• Make sure that the EGT sensor is cleaned properly and it should be retested first before replacing it directly.