Error Code P20C4: What It Means & What To Do?

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Just like other related codes (P20C1, P20C2), OBD error code P20C4 is also a generic powertrain diagnostic trouble code. This means that this generic code applies to all the OBD-II vehicles, but the ways to deal and resolve them may vary from manufacturer to manufacturer. To know how serious this code is and how badly it can affect your vehicle’s engine performance, you will have to go through our subsequent section.

Wondering what this error code means? How can it lead to decline in your engine performance? If YES, then we at PartsAvatar are here to help you out with all your P20C4 error code related queries. Your vehicle uses multiple reductant heaters with different designation. This error code P20C4 will be set by your vehicle’s powertrain control module when it discovers excess voltage in the control circuit “C”. If you want to diagnose it you will need to get hold of a repair manual which will help you to determine which is the “C” circuit for your vehicle. To know more about this error code, take a look at the sections below.

What causes this problem with the Reductant Heater C Control Circuit High?

• Bad or damaged reductant heater
• Open or shorted reductant heater harness
• Poor reductant heater circuit electrical connections

1. Powertrain Control Module - A faulty Power Control Module (PCM) can become irregular to an extent that your car will fail to start or will begin to stall while running. You will notice that exhaust fumes are shorted while the car is running and emissions system control indicators are decreasing. So having a PCM that isn’t working properly is not a good idea, you need to have it replaced right away to resolve the OBD error code P20C4.
2. Reductant Tank Heater -  Definitely, it is a good idea to replace the defective ones with brand new reductant tank heater, considering that P20C4 code indicates issues with your vehicle’s reductant tank heater. You can find with us high quality ones for every make & model on the Canadian roads.
3. EGR System & Parts -  If OBD error code P20C4 is being flashed by your vehicle’s PCM, then chances are that your EGR parts are damaged. If that is the case, you will need to undergo its replacement. You can find with us top notch egr systems and related parts.
4. Diesel Particulate System & Parts - Chances are that there could be a problem with your vehicle’s DEF parts, but don’t let that hold you back, fix your def filters and related parts now. You can find with us top notch def parts at the most budget friendly prices.
5. Catalytic Converter - Catalytic converters in car’s are extremely important to control excessive exhaust emissions. Don’t take a chance and replace the faulty cat converters today. If you need one for your vehicle, you can get one with us today.
6. Diesel Exhaust Fluid  - Low level of diesel exhaust fluid is not something that you should ignore. Take care of your vehicle’s health and buy new one for your vehicle to give your vehicle the desired level of diesel exhaust fluids.
7. Glow Plug Control Module - If you really wish to keep your vehicle’s glow plug in good health, make sure your glow plug control modules are working well. If they are not you might end up having OBD error code P20C4. So, don’t think twice and replace the faulty glow plug control modules today.

Interested in knowing the symptoms to obd code P20C4? If yes, then you have arrived at the right place. We at PartsAvatar have listed out few common symptoms associated with this fuel injector problem.

Common Symptoms

• Excessive black emissions from exhaust system
• Appearance of other related error codes
• Low fuel economy
• Decline in engine performance

After understanding the symptoms and few common causes behind the OBD error code, we are here to help you out in understanding the ways and means to correct the issue. To solve any issue, you need to follow certain steps, and to solve OBD error code P2064, you will need to undergo the following replacements:

• Replace the faulty reductant heater
• Check and replace all the open or shorted reductant heater wires and connectors
• After this, undergo fixing the electrical connections for the reductant heater C control circuit
• Make sure you replace all the faulty catalytic converters and other related exhaust parts
• Also, make sure that your vehicle’s control modules - glow plug control modules and powertrain control module are in best shape, if not, then undergo their replacement at the earliest

Apart from the fuel injector, you might need to undergo few more replacements. You might need PCM, EGR System, Diesel Particulate Filter, Catalytic Converter, Diesel Exhaust Fluid, Reductant Tank Heater, Reductant Heater Harness, Glow Plug Control Module and many other parts. Where to get them from? Well, if you want quality parts, then we can prove to be your dream destination.

It is essential to diagnose this fault code. Here are some steps which a mechanic should follow for diagnosing the problem that triggered a P20C4 code to be stored:

To get started with you will need to get hold of a diagnostic scanner, digital volt/ohmmeter and a reliable source of vehicle diagnostics. It will be really helpful if you could get hold of technical service bulletin (TSB) specific to your vehicle. Believe us it will prove to be extremely helpful for you in your diagnosis process. While choosing a TSB, make sure that it matches your vehicle year, make, and model and also the engine size. To begin your diagnosis, undergo a complete visual inspection of your vehicle’s reductant heater C control Circuit and related harnesses and connectors. Make sure the wires and connectors are not burnt or damaged, in case they are you will need repair or replace them. Now, connect the diagnostic scanner to the diagnostic port of your vehicle and restore all the store codes and freeze the frame data. Not the information and clear all the codes.

After this test drive the vehicle till the vehicles PCM enters the readiness mode or the code is reset. In case of an intermittent code, it will be more difficult to diagnose it as the condition which set this code needs to be worsen in order to diagnose this code. In case the code resets itself, then you will need to look into the vehicle information source to get the diagnostic flow charts flow charts, connector pin out charts, connector face views, as well as component testing procedures and specifications. You will need this information to move on to the next diagnosis step. Make use of the DVOM to check the power supply to the SCR control system. Also, check the fuses with loaded circuit to avoid an sort of misdiagnosis. In case you discover inappropriate power or voltage, then you will need to test the output control circuit voltage. If this voltage turns out to be insufficient then check if the controller is bad or is facing any programming error. In case the voltage output circuit turns out to be within the needed parameters, then use the DVOM to check the reductant heater element for C control Circuit. You can consider as failed if the heater fails to meet manufacturer’s specifications.

Common Mistakes When Diagnosing the P20C4 Code

When you undergo error code P20C4 diagnosis, few misdiagnoses are common. In order to make sure that you don’t commit any, make sure to keep an eye on the following failures:

• Failing glow plug control module
• Failing reductant tank heater
• Troublesome wiring}