Nox Sensors - Engine Light

[2018EcoDieselOwner]

Hi. Had the engine light come on, on my 2018 RAM EcoDiesel. The dealership did a regen and then had me drive it on the highway, which I did for over an hour. This was done last night and the truck has not been driven yet and probably won't be until the weekend, it's now Tuesday Sept. 9/24. I was told that if the Engine light comes back on then the NOX sensors would need to be replaced as a next step, perhaps as they were reading incorrectly during regen, per the mechanic's notes on the order. My question is, do I have to replace the NOX sensors right away as it is not cheap, is there harm in not doing so, if I have had no other problems with the truck? Thanks.

 

[Truckster66!]

Hi. Had the engine light come on, on my 2018 RAM EcoDiesel. The dealership did a regen and then had me drive it on the highway, which I did for over an hour. This was done last night and the truck has not been driven yet and probably won't be until the weekend, it's now Tuesday Sept. 9/24. I was told that if the Engine light comes back on then the NOX sensors would need to be replaced as a next step, perhaps as they were reading incorrectly during regen, per the mechanic's notes on the order. My question is, do I have to replace the NOX sensors right away as it is not cheap, is there harm in not doing so, if I have had no other problems with the truck? Thanks.

I just went through the same thing with my 2018. They first said it was bad DEF fluid, charged $500.00. Three weeks later check engine light came on again.
This time said I need new Cat and both new sensors….$3,700.00.
After my own searching discovered 8 year warranty or 130,000 km warranty on cat…..the dealership claimed not to know about that????
I requested they only change the Cat not the Nox sensors……which they were going to charge $2,700.00 for….they said they would likely break when replacing the Cat…..I told them I wanted the sensors back if they changed them.
After the Cat was changed, surprise , surprise……Nox sensors were fine.
It’s been a month since and all is good!
I drive in the city mostly which causes issues for the regen….have been using Rislone Def and Scr emissions cleaner additive as advised by a friend who is a mechanic to assist in regen issues.
The dealership also killed my battery while it was there…..wanted to replace my battery, then also said I needed a new alternator…..changed battery, not alternator after friend rechecked it and it was fine…..always ask questions….saved me $$$$$

 

[2018EcoDieselOwner]

Based on your experience and I'm sure others more like you, who can anybody trust when our vehicle needs to be fixed? It's pretty pathetic that a dealership cannot be trusted. Thanks for your story.

 

[nickdieselz]

NOx (Nitrogen Oxide) sensors play a crucial role in monitoring and controlling emissions in modern diesel engines, including your EcoDiesel. If they are not functioning properly, the engine control unit (ECU) may not be able to correctly manage the exhaust aftertreatment system, which includes the Diesel Particulate Filter (DPF) and the Selective Catalytic Reduction (SCR) system.

Here’s what can happen if the NOx sensors are not replaced:

1. Emissions Issues: Faulty NOx sensors can lead to inaccurate readings, which may cause the truck to emit higher levels of pollutants than allowed. This can affect emissions compliance and potentially lead to fines or issues passing emissions inspections.

2. Regeneration Problems: Incorrect NOx sensor readings can prevent proper DPF regeneration cycles, which could cause the DPF to clog more frequently, leading to increased backpressure, reduced performance, and eventually, limp mode if not addressed.

3. Check Engine Light: If the sensors are faulty, the check engine light may come back on repeatedly, and the truck may not perform optimally in terms of fuel efficiency or power.

4. SCR System Performance: The SCR system relies on NOx sensor data to inject the proper amount of diesel exhaust fluid (DEF) to reduce NOx emissions. If the sensor is malfunctioning, the SCR system may not function properly, which could lead to further issues and potential damage over time.

While you may not need to replace the NOx sensors immediately if the truck is driving fine, prolonged delays could result in more significant problems. If the engine light comes back on and the issue is confirmed to be with the NOx sensors, it would be a good idea to address it to avoid more expensive repairs down the road. You can also check if there are any extended warranties or emissions-related recalls that might cover the replacement.

 

[2018EcoDieselOwner]

Appreciate the response. Since the Dealership performed the regen, there have been no issues, no Check Engine light warning. I also thought I would be able to perform a regen myself, but I see that that option is not available when I scroll through the system which appears on the dash. Thanks.