AutoCodesDodge – P20EE Dodge

P20EE Dodge Code - SCR NOx Catalyst Efficiency Below Threshold Bank 1

Quick Answer

The aftertreatment system is equipped with two Nox Sensors. Common causes include Faulty NOx Sensor, Diesel Exhaust Fluid, Faulty Selective Catalyst Reduction (SCR) Catalyst. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P20EE Dodge indicates SCR NOx Catalyst Efficiency Below Threshold Bank 1.
Common causes
Common causes include Faulty NOx Sensor, Diesel Exhaust Fluid, Faulty Selective Catalyst Reduction (SCR) Catalyst.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code Popularity 25,877
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on May 09, 2022
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Code P20EE Dodge Description

The aftertreatment system is equipped with two Nox Sensors. The upstream NOx Sensor 1/1 is located at the inlet elbow of the Diesel Exhaust Oxidation (DOC) Catalyst/Diesel Particulate Filter (DPF) and is permanently connected (via a permanent wiring harness) to the NOx Sensor 1/1 Module mounted toward the front frame rail at the rear of the right front wheel well. The downstream NOx Sensor 1/2 is located at the outlet of the Selective Catalytic Reduction (SCR) Catalyst and is permanently connected (via a permanent wiring harness) to the NOx Sensor Module 1/2 mounted along the left middle frame rail. The upstream NOx Sensor 1/1 measures the NOx concentration upstream of the Catalysts. The downstream NOx Sensor 1/2 measures the NOx concentration downstream of the Catalysts. The NOx Sensors also perform a heater strategy. The NOx Sensor module monitors the sensor temperature and operates a heater inside the NOx Sensor probe to maintain proper sensor operating temperature. The NOx Sensors are smart devices and communicate with the Powertrain Control Module (PCM) over designated Data Link circuits. The NOx Sensors perform their own internal diagnostics and report malfunctions back to the PCM. The NOx Sensors are used to monitor the efficiency of the SCR Catalyst and dosing system. The PCM will illuminate the MIL lamp immediately after the monitor runs and fails.
OBDII Code P20EE Dodge - SCR NOx Catalyst Efficiency Below Threshold Bank 1 - AutoCodes.com
P20EE Dodge Code - SCR NOx Catalyst Efficiency Below Threshold Bank 1

What are the Possible Causes of the DTC P20EE Dodge?

  • Faulty NOx Sensor
  • Diesel Exhaust Fluid
  • Faulty Selective Catalyst Reduction (SCR) Catalyst

How to Fix the DTC P20EE Dodge?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P20EE Dodge code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P20EE Dodge Code

1. What are common symptoms of OBDII code P20EE in a Dodge, indicating SCR NOx Catalyst Efficiency Below Threshold Bank 1?

- Common symptoms include the illumination of the Check Engine Light, reduced engine performance, and potential exhaust system issues.

2. What are possible causes of the OBDII code P20EE in a Dodge, indicating SCR NOx Catalyst Efficiency Below Threshold Bank 1?

- Potential causes include a faulty NOx sensor, issues with the Selective Catalytic Reduction (SCR) system, poor quality DEF (Diesel Exhaust Fluid), or exhaust leaks.

3. How can I diagnose the OBDII code P20EE in my Dodge related to SCR NOx Catalyst Efficiency Below Threshold Bank 1?

- Diagnose by performing a thorough visual inspection of the exhaust system, checking the NOx sensor functionality, and ensuring proper DEF quality and levels.

4. Can I drive my Dodge with the OBDII code P20EE present?

- It is not recommended to drive with the code present as it can lead to increased emissions, potential damage to the catalytic converter, and reduced fuel efficiency.

5. How can I repair the OBDII code P20EE in my Dodge indicating SCR NOx Catalyst Efficiency Below Threshold Bank 1?

- Repair options may include replacing the NOx sensor, addressing SCR system issues, ensuring DEF quality, fixing exhaust leaks, and clearing the error code.

6. Is it possible to reset the OBDII code P20EE in a Dodge without addressing the underlying issue?

- While clearing the code may temporarily turn off the Check Engine Light, it is crucial to address the root cause to prevent further damage and ensure proper vehicle operation.

7. What is the role of the SCR NOx Catalyst in a Dodge's emission control system?

- The SCR NOx Catalyst helps reduce nitrogen oxide emissions by converting them into nitrogen and water vapor through the use of DEF in the exhaust system.

8. How often should I check the DEF (Diesel Exhaust Fluid) level in my Dodge to prevent issues related to the OBDII code P20EE?

- It is recommended to regularly check the DEF level and quality as part of routine maintenance to ensure proper operation of the SCR system and prevent code P20EE.

9. Can extreme weather conditions affect the SCR NOx Catalyst efficiency in a Dodge and trigger the OBDII code P20EE?

- Yes, extreme temperatures or weather conditions can impact the performance of the SCR system, leading to potential efficiency issues and triggering the code P20EE.

10. Are there any preventive maintenance tips to avoid encountering the OBDII code P20EE related to SCR NOx Catalyst efficiency in my Dodge?

- Regularly servicing the SCR system, using high-quality DEF, driving at optimal speeds, and avoiding engine modifications can help prevent issues leading to the code P20EE.

Discuss the causes and fixes for P20EE Dodge OBDII Code

  • got this code after doing recall 67A. Replaced the CAT, DEF injector and upstream NOx sensor. Code still comes on. Any help??

    • The P20EE - SCR NOx Catalyst Efficiency Below Threshold Bank 1 code indicates that the selective catalytic reduction (SCR) system isn't reducing NOx emissions effectively. Since you’ve already replaced the catalytic converter (CAT), DEF injector, and upstream NOx sensor, it’s frustrating that the code persists. Here are some potential reasons and troubleshooting steps:

      Potential Causes:

      1. Downstream NOx Sensor Issue: The downstream NOx sensor monitors the SCR system's efficiency. If it’s faulty or out of calibration, it may falsely trigger the code.
      2. DEF Quality or Contamination: Poor-quality DEF or contamination in the tank can affect SCR system performance.
      3. Exhaust System Leaks: Even small leaks upstream of the SCR system can skew sensor readings and lead to inefficiency.
      4. ECU Calibration or Software Update: Sometimes, the ECU needs to be updated or recalibrated after significant repairs or recalls like 67A.
      5. Incomplete System Reset: The SCR system may need a forced regeneration or reset after component replacements to clear learned adaptations.

      Troubleshooting Steps:

      1. Inspect the Downstream NOx Sensor:

        • Check for damage, contamination, or incorrect installation.
        • Use a diagnostic tool to monitor real-time NOx sensor readings. Compare the upstream and downstream values—if they’re nearly identical, the downstream sensor may be faulty.
      2. Test DEF Quality:

        • Verify the DEF meets ISO 22241 standards (32.5% urea concentration).
        • Use a refractometer or DEF tester to ensure proper quality.
        • Drain and refill the DEF tank if contamination is suspected.
      3. Check for Exhaust Leaks:

        • Inspect the exhaust system for leaks or loose connections, particularly upstream of the SCR.
        • Even minor leaks can disrupt NOx sensor readings and reduce SCR performance.
      4. Perform an SCR Reset and Adaptation:

        • Use a capable diagnostic tool to reset SCR adaptations and initiate a forced regeneration if applicable.
        • Some systems also allow you to perform a NOx sensor relearn procedure.
      5. Verify ECU Updates:

        • Confirm that the dealership completed all necessary updates as part of the 67A recall.
        • Ask about any post-repair software calibrations required for the new components to function correctly.
      6. Double-Check Installation:

        • Ensure all replaced components (CAT, DEF injector, sensors) are correctly installed and connected without pinched wires or misaligned parts.

      Next Steps:

      If these steps don’t resolve the issue, I recommend consulting a Dodge dealer or a shop experienced with emissions systems. They may need to dig deeper into ECU settings or perform advanced diagnostics like NOx sensor calibration under specific driving conditions.

      Let us know how these steps work out or if you need additional guidance!

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