Guide To P20CB OBD Error Code Solutions

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Wondering on how to diagnose the error code P20CB? Here’s all you need to know about the error code P20CB. This generic OBD-II code powertrain control module (PCM) failure is also referred to as an exhaust aftertreatment fuel injector "A" control circuit/open. While altering the leftover exhaust particles into harmless gases, the diesel exhaust fluid (DEF) is used. It should be noted that, in order to burn off those particles, an increased temperature in the exhaust system is required. The temperature of the diesel particulate filter is brought to the optimum level through the injections of the DEF fluid into the exhaust system. Only then the system is able to convert the hazardous NOx to nitrogen, carbon dioxide and water. The code P20CB is stored, whenever the DEF injector fails to function correctly.

It can be seen that the outlet of the turbocharger sub-assembly has the exhaust fuel addition injector assembly built in. The exhaust fuel addition injector assembly receives the low-pressure fluid through the feed pump in the supply pump assembly. Through a control signal from the engine control module (ECM), the exhaust fuel addition injector assembly adds the fuel. This injector is further utilized for two different control: particulate matter (PM) forced regeneration and PM reduction.

What causes this problem with the Exhaust Aftertreatment Fuel Injector A Control Circuit/Open?

• A damaged exhaust aftertreatment fuel injector
• The harness in the exhaust aftertreatment fuel injector open or short circuited
• A weak electrical connection in the exhaust aftertreatment fuel injector circuit

1. Powertrain Control Module - A faulty powertrain control module is likely to invite issues like a poorly running engine, increase in carbon emission, choking, stuttering and stalling of the engine. Well, to avoid these, we recommend a replacement or repair of the powertrain control module before it worsens the condition of the system.
2. Diesel Exhaust Fluid Pump - Experiencing a loss in the efficiency of the DEF pump? Yes, it is likely to happen due to a bad diesel exhaust fluid. We advise you to get your diesel exhaust fluid pump changed right away.
3. Exhaust Aftertreatment Fuel Injector - A damaged exhaust aftertreatment fuel injector is likely to arise a lot issues including a fall in the fuel efficiency and a diminished engine performance. It is advised to get your exhaust aftertreatment fuel injector changed or repaired right away to get rid of these problems caused by the error P20CB.
4. Fuel Injector - Difficulty in starting the vehicle? Poor idle? Rough engine performance? All these are triggered due to your damaged fuel injector. Now get your error code fixed with Parts Avatar. Log in now for your new fuel injectors offered at just the right prices.
5. Diesel Particulate Filter - Observing a acrid smell near the engine? Yes, it is due to a jammed or damaged diesel particulate filter. Tune into the Parts Avatar for your new diesel particulate filter. What are you waiting for?
6. Ohmmeter - This diagnostic tool is essential while diagnosing the error code as it helps in measuring the electrical resistance, the opposition to an electric current. Tune into Parts Avatar to get your hands on premium quality ohmmeters.
7. DEF Injector - A distorted DEF injector causes a rough idle, a fall in the engine performance and a lot more than just the error code P20CB. Get your code fixed with a new DEF injector now! Log into Parts Avatar.

Willing to know some common symptoms of OBD Code P20CB? Your wish is our demand. Have a look at them below:

Common Symptoms

• Falling engine performance
• Immoderate black smoke from vehicle exhaust
• A significant decrease in the fuel efficiency
• Other EAS/SCR codes that are relatable

We have listed out some ways which would help you to correct the occurrence of OBD Code P20CB. They are mentioned here as follows:

• Mend or restore a corroded or open harness in the exhaust aftertreatment fuel injector
• Measures should be taken to fix a faulty exhaust aftertreatment fuel injector
• Repair or replace a weak electrical connection in the exhaust aftertreatment fuel injector circuit
• 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 PCM, diesel exhaust fluid, exhaust aftertreatment fuel injector, fuel injector, diesel particulate filter, EAS, ohmmeter, DEF injector, automatic transmission module and a lot more. We are sure that now all your issues would be resolved.

It is essential to diagnose this fault code. Here are some steps which a mechanic should follow for diagnosing the problem that triggered a P20CB code to be stored:

To begin with, use a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle specific diagnostic to diagnose the error code P20CB.

It can be really helpful if you are successfully able to find a technical service bulletin (TSB) that parallels the vehicle year, make/model as well as the engine size, code/s stored, and symptoms displayed.

A visual inspection of the EAS wiring harnesses and connectors should be performed. All the corroded or damaged wiring and connectors should be mended or restored before moving to the next step.

Next, the scanner should be connected to the vehicle diagnostic connector to retrieve all stored codes and relevant freeze frame data.

It is advised to register this information (before clearing the codes) as it proves to be quite helpful. The vehicle should then be test driven until the PCM either enters readiness mode or the code is reappears.

If in case, the PCM enters readiness mode, the code is intermittent and will be quite challenging to diagnose. It should be noted that at times, the conditions which added to the code being stored may need to worsen before an accurate diagnosis can be performed.

While if the code reappears immediately, it is recommended to search for the vehicle information source to obtain diagnostic flow charts, connector pin-out charts, connector face views along with the component testing procedures and specifications. All this is essential to proceed forward with the diagnosis. The vehicle information source should be used to pinpoint the exact location of EAS fuel injector A.

The DVOM should be employed to probe (voltage drop) the power supply to the EAS control system. All the fuses should be tested with the circuit loaded to prevent a misdiagnosis. If you find the required power (battery voltage) and ground circuits, utilize the scanner to actuate the EAS fuel injector (solenoid) and examine the output control circuit voltage.

Also, if the voltage inadequate, a damaged controller or a programming error should be suspected. While, if the voltage output circuit falls within the parameters, the DVOM should be used to test the EAS fuel injector. A failure in the injector should be suspected, if it fails to fall within the manufacturer’ specifications.

Common Mistakes When Diagnosing the P20CB Code

Here we have listed a few common mistakes that should be avoided while diagnosing the error code P20CB:

• A fault in the DEF injector
• A malfunctioning PCM
• Wiring problems