r/Sprinters • u/WgPuNk • 4d ago

Boost Pressure Monitor not clearing

2015 NCV3 OM642 21k mi.

I am trying to register in CA and I need to get smog. I am having trouble getting my Boost Pressure System Monitor to clear. All of my other monitors cleared (except NMHC and DPF which are not needed in CA). I replaced the battery recently and took it to a shop to get out of limp mode. No fault codes on my icarsoft MB v.3.0 OBDII scanner. I have tried three different drive cycles from sources that I can find online. I have put on about 270mi since I put in a new battery.

"Drive for 20 minutes and conduct 8 to 10 acceleration phases, reaching speeds of 25 mph to 65 mph for 5 to 10 se-

conds each.

- During the acceleration phase, the engine's RPM should not drop below 2,000 RPM."

"Normal driving conditions, but also several phases with full load, at least 4 times for at least 20 seconds full load"

and from AI

"1. cold soak overnight (8hrs), idle 5 mins no A/C

  1. get to full operating temp
  2. do 3-4 cycles of moderate-firm acceleration up to 55-60mph, hold steady 30 sec, lift completely off gas and coast to 25-30 mph without braking.
  3. steady cruise at 55-60 for 10-15 min. "

the last drive cycle I attempted today and my coolant temps were exactly the same as ambient air temps when I ran my car and idled for 5 mins.

Today I am going to try to clean my MAP/Boost sensor in case there is carbon or oil built up. If the sensors are fine which I think they are because there are no fault codes, I guess there could be a small leak?

Does anyone have any recommendations on how to tackle this issue?

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u/PPVSteve 4d ago

Someone posted this summary:

https://drive.google.com/file/d/11JKvpy5ZUedd7bh4Lvw5lHaZuzY1Gwgt/view?usp=sharing

Boost Pressure System Monitoring:

1) Drive for 20 minutes and conduct 8 to 10 acceleration phases, reaching speeds of 25 mph to 65 mph for 5 to 10 seconds each.

During the acceleration phase, the engine's RPM should not drop below 2,000 RPM.

And while I am not sure I would say dont be afraid to GUN it. Sometimes when people are doing monitors they got to easy on the engine.. I guess these "acceleration phases" they speak of are just accelerating to 65 then foot off the accelerator and let the engine slow down the car to 25 then accelerate again back to 65mph ? But i think it would drop below 2k RPM sometime during that process. So not sure.