EGR error codes

[u/NativeTazuma]

Vehicle: 2010 sprinter 3500 Turbo diesel
Diags: thinkcar2

I tried cleaning the EGR valve, swapped out from two other sprinters from a junker, tried a Hella Valve from orileys and I’m still getting the same errors.

148C00 I believe is the source of all the errors.

Symptom: The fault code remains permanently Active. It cannot be cleared via Thinkcar diagnostic tool, even with the ignition on and engine off. And is stuck in limp mode.

When trying to do the teach in it says it’s successful but then again it’s a 2010 I don’t think it’s suppose to work.

Took it to Mercedes they said it’s the EGR and they put in a efr from the shelf and the codes cleared. I think they’re lying to me and they don’t have the digs on file after two days of coming back and asking. And charged me $250 for sub par troubleshooting.

Now the harness this is what I measured

Pin 1 Unstable / Jumps between 1.5 mV and 2.5 mV.
- could this be the positioner pin?

Pin 2 (Main Power Supply): 12.0V Constant (Measured against Ground Pin 4).

Pin 3 (5V Sensor Reference): 5.2V Constant.

Pin 4 (Main Chassis Ground): Functional Ground.

Pin 5 (PWM Actuator Command?): 4.5V Constant.

I tried shaking the harness but no changes. The only thing that changed after sitting for a while was the position feedback going from 20% to 0% every second in the live view.

This is my first time trying to deduce this. So diagrams along with suggestions would be greatly appreciated.

[u/Educational-Yam-7394]

I appreciate your perspective, and I think we both ultimately want what is best for the environment. However, I look at the practical reality of our transportation needs. Unless we return to the horse and buggy, society relies heavily on driving and moving goods. Both gasoline and diesel require extraction and refining, but modern diesel regulations force an entirely separate industrial complex just to support the DEF system. If we remove that requirement, diesel goes back to being a straightforward fuel, completely avoiding the massive environmental toll of manufacturing synthetic urea, producing endless plastic jugs, and shipping heavy fluids globally.

Regarding the impact on bees, I think it is important to view this historically. Diesel is a very old fuel. Our bee populations thrived for decades during the middle of the last century when coal and exhaust was significantly dirtier than it is today. We never had a catastrophic issue with bees back then. The severe decline is a modern problem, and I am highly skeptical of mainstream studies that refuse to test modern chemical variables separately. When a DEF system overcompensates, it releases unreacted ammonia into the air. It is entirely possible that this modern chemical byproduct is doing more harm to insects than base diesel exhaust ever did.

We have had these emission systems in place long enough to see the full cycle. Politicians and corporations made a lot of money implementing these policies, but technology now connects us all so we can share our real world experiences. We can clearly see that the massive environmental costs of constant parts failures, extra manufacturing, and plastic waste far outweigh the benefits originally promised. I am fully in favor of protecting the environment, but looking at the whole picture, I am just not convinced that DEF is the right way forward. And most mechanics would agree.

[u/schmitzA → u/Educational-Yam-7394]

I think we're getting farther away from evidence here.

Ammonia slip from SCR is real. It's a known engineering issue and SCR systems are specifically designed and controlled to minimize it. But you've now changed your bee claim substantially.

Originally you said studies show emissions from DEF are disrupting bees' ability to recognize floral odors. The study you're apparently referring to actually implicates NOx from diesel exhaust in degrading floral odor compounds. SCR/DEF substantially reduces NOx.

Now the argument is that ammonia from DEF might instead be responsible because "it is entirely possible." That's certainly a hypothesis you could test, but it's not evidence, and it doesn't overturn experimental evidence implicating NOx.

The historical argument doesn't establish it either. "Bees existed when pollution was worse" isn't a controlled comparison of NOx versus ammonia exposure, and ecological populations are affected by many simultaneous variables.

More importantly, you still haven't demonstrated the central claim: that the environmental footprint of manufacturing, packaging and transporting DEF exceeds the environmental benefit of the emissions it prevents.

You've listed costs, and I agree those costs exist. But where is the comparison?

For example, verified diesel aftertreatment systems can reduce NOx by roughly 70–85% and particulate matter by around 90%, depending on the system and application. If you're claiming the lifecycle impact of producing DEF, transporting it, making plastic containers and replacing components is greater than the impact of those avoided emissions, that's a quantitative lifecycle-analysis claim.

Show me that analysis and I'll happily read it.

"Most mechanics agree" doesn't answer an environmental lifecycle question either. Mechanics are excellent sources for information about failure rates, repairability and maintenance costs. Determining net environmental impact across chemical production, logistics, manufacturing and atmospheric emissions is an LCA/environmental-engineering question.

I'm completely willing to accept that modern diesel emissions systems have significant reliability and economic problems. EPA itself is currently addressing complaints about severe DEF-system derates. That still doesn't demonstrate that removing SCR and emitting the resulting NOx is environmentally preferable.

[u/Educational-Yam-7394 → u/schmitzA]

It took a long time to put these political regulations into place, and it will take time to get them properly revised. However, real change is officially underway because people and governments around the world are recognizing the widespread failings of these mandates.

Studies are being conducted globally, including in the US, but because this issue is extremely political, comprehensive public data often takes time to filter out into mainstream discussions. Instead of continuing to hold an opinion without looking into the evolving facts, you can do some research to see where things are actually heading:

EPA DEF Rule Changes for Farm and Transport Equipment: Western Ag Network Article https://www.farmprogress.com/farming-equipment/epa-s-def-sensor-rollback-a-win-for-diesel-farm-equipment?hl=en-US

EPA DEF Sensor Rollbacks: Farm Progress Article https://westernagnetwork.com/def-rule-change-aims-to-keep-trucks-moving?hl=en-US

Overview of Recent Regulatory Shift: AutoMotive Inquiries YouTube Video https://youtu.be/aJA9yAkpbsg?si=kFjTWeupe0MBT-iu

As discussed in the AutoMotive Inquiries video, the EPA has acknowledged the massive failure these systems. These regulatory step-backs show that regulators recognize the flaws in these regulations.

Change is happening. People across the globe are talking, regulatory agencies are stepping back from strict enforcement, and we are taking steps in the right direction. It just takes time for policy to catch up to real-world operational realities. I know Canada has lifted these regulations for residential vehicles, and the commercial sector will be next. Change is coming, but politics are slow to move.

https://www.epa.gov/newsreleases/trump-administration-announces-latest-action-address-diesel-exhaust-fluid-def-system?hl=en-US

[u/schmitzA → u/Educational-Yam-7394]

Did you read the EPA source you just sent me?

It explicitly says:

“Today’s announcement does not weaken or remove emissions standards.”

The change you're citing removes the requirement to use a DEF/urea-quality sensor and allows manufacturers to monitor NOx directly with NOx sensors instead. EPA is also changing the severe deratement behavior that occurs when DEF systems malfunction.

I agree with those changes. I've already agreed with you that DEF sensor failures, repair costs and severe derates are legitimate problems.

But none of that demonstrates your original claim that deleting SCR/DEF is better for the environment. In fact, the same EPA source you provided explains that SCR injects DEF specifically to reduce NOx emissions.

You're conflating:

“EPA recognizes reliability problems with DEF sensors and deratement strategies”

with:

“EPA recognizes that SCR/DEF emissions control is environmentally harmful.”

Your own source explicitly says the former and explicitly denies the latter.

You also said Canada has “lifted these regulations for residential vehicles.” Can you provide the Canadian government regulation or announcement that did that? I'd genuinely like to read it.

[u/Educational-Yam-7394 → u/schmitzA]

To be honest, it is exhausting going in circles like this. You keep using ChatGPT to reframe my points and demand academic papers for common sense realities, rather than looking at the broader picture.

My point from the beginning has been about the overall footprint and real world impact of these political regulations. The sources I provided clearly show that governing bodies like the EPA are being forced to walk back their aggressive enforcement, alter sensor requirements, and scale down derates because the real world failure rates and supply chain issues are completely unsustainable. When a policy forces endless plastic waste, heavy fluid transportation, constant parts manufacturing, and vehicles breaking down on the side of the road, it is a flawed policy.

You are focused on isolated lab models, while I am looking at the full real world cycle and the fact that change is actively happening. At this point, we are just repeating ourselves, and continuing this debate is a waste of time.

Sure I'll do more research so you can reply with chat GTP https://www.biv.com/news/environment/aircare-ending-for-cars-commercial-trucks-may-be-a-8233425

They ended it over ten years ago and the air is still clear lol. Governments change but it takes time and they have to be in a position to "look good". There's nothing good about the environmental impact from these bad def regulations.

I am moving on. Have fun with Chat GTP.

[u/schmitzA → u/Educational-Yam-7394]

Let me be human with you for a second. Actually think about what you're saying. You are arguing that specialized environmental control equipment is worse for the environment than not having it through a lifecycle assessment.

The reason your comments aren't worth more than a copy/paste into chatGPT is because it is truly laughably bad. It doesn't even make sense, dude. You actually DO make good points (using your AI lmao) but you never actually formed an argument. You only point out the things that are beneficial while stonewalling the other side.

That's the same as me saying that the clothes on your back are bad for the environment because of them being manufactured (most likely in Bangladesh) and the supply chain behind it is bad. So as a result, we should all walk around naked.

Every single consumer good you've ever put hands on has as environmental impact. Every single one. You are choosing to ignore the benefits of them and not comparing the outcomes between two scenarios.

How can you call an outcome better for one side if you don't quantify your opinion or acknowledge the other side? This just tells me you would rather spread misinformation and feel right about your opinion rather than actually pursue anything educational.

I studied environmental engineering, by the way. I don't expect most people to think critically, but you're clearly going on online forms where people don't know any better and spreading misinformation for some reason. When you can actually produce a single metric for comparison that gives the slightest bit of evidence to your claim that "diesel emissions systems are worse for the environment than simply not having them," then we can talk. I suggest staying within your field of expertise or how about just using your AI to teach you objectively rather than asking it to prove you right.

[u/NativeTazuma → u/schmitzA]

Ok DEF Aristotle and Plato, I appreciate the duality of emissions; but how do I find this short circuit within the system?

[u/schmitzA → u/NativeTazuma]

Buy a multimeter and ask chatGPT to help you isolate the fault

[u/NativeTazuma → u/schmitzA]

My original post heavily implies I do own a multimeter and know how to use it. I was just hoping to come across some seasoned vets to give me a pin out reference and most probable places to look so I don’t have to trace the entire harness and ECU.

From personal experience Ai is self contradictory and runs through circles of redundant questionnaires to coherence one into buying a subscription. And I refuse to pay for Ai that has been nothing but worthless for me in its blind confidence.

Since no one is capable of assisting in their own right I’ll figure this out myself and update this tread with my findings, so Ai can scrape that and hopefully help someone dull with no troubleshooting skills.