Duramax engine is extremely popular for its reliability and higher horsepower. Though the engine shows problems after reaching 100,000+ miles, it can trigger a P20EE error code after only 50,000 miles. So as an owner of this engine, you should have a clear understanding of OBD2 P20EE code Duramax.
A vehicle with a Duramax engine can set a P20EE code due to a faulty NOx sensor or a DEF system issue that shows symptoms like active CEL, an error message on the dashboard, and reduced engine performance. Since it requires deep troubleshooting and higher skill, it’s better to hire an expert mechanic to fix the error code.
Article Summary
What Does P20EE Code Duramax Mean?
The P20EE code refers to SCR NOx catalyst efficiency below the threshold. It means the PCM identifies that the catalyst efficiency is under bank 1’s threshold.
The DEF (diesel exhaust fluid) helps convert harmful NOx into N2CO2 and water. After adding DEF to the SCR catalyst, it performs a chemical reaction. The PCM monitors the SCR catalyst’s efficiency using the NOx sensors. When the SCR catalyst can’t perform its job efficiently, the computer stores the P20EE code.
The P20EE code may also be activated due to a DEF system issue and it can bring other error codes like P20ED, P20EC, and P20EF.
The DEF also helps convert the leftover exhaust particles into non-toxic gases. The exhaust system’s temperature needs to rise to burn the leftover particles.
So, P20EE code won’t store until the coolant temperature is above 70C. The P20EE code won’t also run if the ambient temperature is above -7C or 20F.
Causes of Duramax P20EE OBD2 Error Code
Lots of causes can trigger P20EE generic code and below are some most common reasons:
- DEF contamination or injector failure
- Faulty NOx sensor or exhaust gas temperature sensor
- SCR failure
- Insufficient DEF fluid
- Faulty wires or poor connection
- Leak exhaust system
- Control module problem
Symptoms of Duramax P20EE OBD2 Error Code
Though you need to run the OBD2 scanner to verify if it is a P20EE code, some symptoms also indicate that the car’s computer set a P20EE error code:
- Check engine light comes on
- Exhaust system warning message on the car’s dashboard
- Poor fuel efficiency
- Reduced engine performance
- Failure of DPF regeneration
- Excess black smoke coming out from the exhaust
How To Diagnose Duramax P20EE OBD2 Code?
The P20EE error code may set various makes and models with the Duramax engine. So the process of troubleshooting this generic code varies based on certain vehicles. Below is a common process for diagnosing P20EE code:
- Connect the OBD2 scanner to the vehicle and scan for the error codes in the ECM. Check the freeze frame data to get the failure codes.
- Check the history reports of your vehicle if there are any NOx-related error codes.
- Inspect the tailpipe for black smoke and the exhaust system for damage or leaks.
- Check the hose fittings for obstructions.
- Inspect SCR Catalyst for any symptoms of damage or flameouts.
- Check the DEF fill tube for cap integrity and leaks.
- Inspect the DTC status and make sure the SCR system is enabled.
- Check the engine for damage or excess fuel consumption that can happen due to turbo boost drop or injector misfire.
How to Fix Duramax P20EE OBD2 Error Code?
Though the causes and symptoms of P20EE are quite the same as various engine codes, the fixing process varies depending on the vehicle’s make and model. So it may require an expert hand and plenty of tools to fix the P20EE code.
It’s significant to ensure the after-treatment hardware is working reliably. In most cases, the P20EE doesn’t set due to the reductant injector’s intermittent hardware failure or serious NOx catalyst issue.
Certain drive cycles trigger temporary ammonia overload and it sets the P20EE generic code falsely. If so, you won’t have to replace any hardware to fix the code. Instead, you have to perform a two-step stationary procedure or DPF regeneration process to evaluate the SCR system properly. After completing the procedure, you must cycle off the ignition for a minimum of three minutes after opening and closing the driver’s door.
If you can complete the DPF regeneration process and it fixes the P20EE, you can then start driving the car confidently. But if the error code comes back during performing the diagnostic drive, check the DEF injector for proper flow. if the DEF injector flowing properly to the specifications, check the DEF fluid.
If you can’t perform these procedures or still get the error code, leave the job to an expert mechanic.
Can You Still Drive with P20EE Code Duramax?
Driving a car with a P20EE code won’t damage anything. So you can keep driving. The code is related to the NOx sensor and DEF system. If it comes out as a NOx issue, you shouldn’t be much worried. But if the P20EE error code activates due to the DEF system, it’s a bit concerning.
However, in both cases, your car may show reduced power massage and activate limp mode due to driving for longer. So your car might not run over 5 mph uphill and over 40 mph on a flat surface. If you ignore the P20EE message for long, your car may not move at all.
P20EE error code may also come out due to catalyst inefficiency below the threshold and pop up the DEF fluid quality poor. It can cause your car’s DEF quality test to fail. in worse cases, you may need to replace the NOx sensor. So bring the car to the dealer or nearest service center after diagnosing the P20EE code on your car with the Duramax engine.
Also Read: P2510 Code Duramax
FAQs
How Much Does It Cost to Fix P20EE?
The cost of fixing the P20EE error code varies depending on the source of the issue, the make and model of the vehicle, and the auto shop. However, most auto shops charge around $75 to $150 to diagnose the error code and it typically takes one hour of labor.
Does the Blue Smoke Trigger the P20EE Error Code?
Yes, your car’s computer can set the p20ee code if excess blue smoke comes out from the exhaust system. It indicates problems with the Duramax engine burning engine oil and the oil reaches the engine components. It’s a severe problem and can damage the injector pump.
Can a Car Run without a NOx Sensor?
NOx sensor is a vital component that protects the engine and after-treatment system. Without the NOx sensor, ECU can send the vehicle into limp mode during driving and cause the engine to Derate. So if you have a faulty NOx sensor, fix it as soon as possible.
Final Words
Though the P20EE code Duramax doesn’t cause any immediate issues, you shouldn’t ignore it for too long. If the faulty DEF system or NOx sensor triggers the code, your car may fail the emission test and you experience reduced engine performance.
It can be extremely irritating if your car activates limp mode due to the p20EE code. So inspect the car by an expert mechanic after having this generic code and fix it, particularly before going for a long drive.
