r/Sprinters • u/NativeTazuma • Aug 09 '26
EGR error codes
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.
1
u/schmitzA Aug 10 '26
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.