# DPF Differential Pressure: What's Normal vs Excessive?



## SPL15 (Feb 3, 2019)

What's "Normal" vs "Excessive" DPF differential pressure? Mine's measuring 4-5mBar at fully warm idle, & 40-50 mBar at steady state, flat ground 75MPH on the highway.

Recently bought a super nice condition 2012 E70 35d w/ 150K miles from a BMW dealership for an awesome price due to the persistent 452A code & the BMW dealership's insistence that the DPF will need to be replaced ASAP.

2K miles so far; literally not one issue or check engine light. Re-gens appear to be occurring about 150-200 miles apart.

Pretty sure the dealership was expecting to recoup some of the price reduction w/ me bringing the car back for a DPF replacement soon after I bought it (sometimes it pays to pretend that you're stupid & naive )... DPF will be "recycled" in an environmentally friendly manner, & replaced w/ a MUCH less restrictive aftermarket part once the weather warms up 

Bought a code scan tool yesterday, where about 50 miles after the last regen, live data shows 4-5 mBar differential pressure across the DPF at idle, where it rises to between 40-50 mBar at steady state 75 MPH on the highway. No stored codes relating to DPF issues, except for the 452A code that, from what I understand, essentially means your DPF is old & is nearing EOL.

What's considered "Normal" vs "Excessive" differential pressure across the DPF? I'm more asking for academic reasons / FYI as I continue to monitor things, as everything is working perfectly fine, for now...

I've seen BMW's "Max Permissible" measurements of 65 mBar at idle, & 150mBar at 2K RPM; my readings are WELL below this, but would be interested to know what others are getting. Might also be useful as a dataset for troubleshooting as more E90 & E70 diesels approach the 120K - 150K+ mile range w/ new, less knowledgeable owners behind the wheel after the 1st or 2nd owner traded them in for a new car.


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## n1das (Jul 22, 2013)

SPL15 said:


> What's "Normal" vs "Excessive" DPF differential pressure? Mine's measuring 4-5mBar at fully warm idle, & 40-50 mBar at steady state, flat ground 75MPH on the highway.
> 
> Recently bought a super nice condition 2012 E70 35d w/ 150K miles from a BMW dealership for an awesome price due to the persistent 452A code & the BMW dealership's insistence that the DPF will need to be replaced ASAP.
> 
> ...


Sounds like you got a deal on an X5 35d due to the dealer's willingness to throw parts at it at the customer's expense.

The 452A code is an information code only for BMW service to advise the customer that the DPF is approaching it's calculated end of life and they should make an appointment for a $4800 DPF replacement. The code DOES NOT mean that the DPF needs to be replaced immediately.

The remaining DPF life is a calculated value based on a number of factors. The 452A code typically gets triggered around 150k miles. My 12 X5 35d triggered the 452A code around 155k miles.

When the miles on the car exceeds the calculated life of the DPF, code 4D4A gets triggered and is persistent like the 452A code. The code is another information code which means the miles on the car has exceeded the calculated life of the DPF because the car continued to be driven. The code causes a warning message about the DPF to be displayed ONCE at exactly 10 minutes after startup. The car basically starts nagging the owner more about the DPF but has no other effect. Just clear the message and drive on. You don't have to do anything about the DPF yet.

My 12 X5 35d triggered the 4D4A code around 171k miles. I regularly check DPF data with the Carly app and Bluetooth dongle to know that DPF regens are happening normally.

You don't necessarily have to do anything about the DPF yet but do keep an eye on the data to know that regens are happening like they should. My 12 X5 35d is only at 210k miles and it still has the original DPF. The car has no driveability issues and I regularly check on the DPF status with the Carly app. I'm keeping an eye on the DPF and expect it will be a while before I actually have to do anything about the DPF.

Good luck and congrats on your new ride.

Sent from my XP8800 using Tapatalk


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## n1das (Jul 22, 2013)

Anybody in the market for a used X5 35d should consider taking advantage of BMW dealer ignorance of the 452A code to help negotiate a lower price on the car. The 452A code DOES NOT mean the DPF has to be replaced immediately but is approaching the calculated end of life.

Skilled negotiators in the market for a used X5 35d can potentially find some deals.

Sent from my XP8800 using Tapatalk


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## SPL15 (Feb 3, 2019)

n1das said:


> Anybody in the market for a used X5 35d should consider taking advantage of BMW dealer ignorance of the 452A code to help negotiate a lower price on the car. The 452A code DOES NOT mean the DPF has to be replaced immediately but is approaching the calculated end of life.
> 
> Skilled negotiators in the market for a used X5 35d can potentially find some deals.
> 
> Sent from my XP8800 using Tapatalk


That's precisely what I did, along with the worn out front torsion arm brackets, thermostat, & a few other minor items that were listed on the PPI. Have been looking for something like this for a while (ie an otherwise awesome condition LCI E70 that has a worn out DPF)

Also, good to see another HAM on here


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## YOYO 02 (Oct 27, 2021)

n1das said:


> Sounds like you got a deal on an X5 35d due to the dealer's willingness to throw parts at it at the customer's expense.
> 
> The 452A code is an information code only for BMW service to advise the customer that the DPF is approaching it's calculated end of life and they should make an appointment for a $4800 DPF replacement. The code DOES NOT mean that the DPF needs to be replaced immediately.
> 
> ...


Bonjour, j'ai le voyant DPF qui s'allume au bout de 10 minutes les codes defauts sont 480A / 481A / 4D00 mais la voiture roule tres bien. faut il changer le DPF?
MERCI


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## Doug Huffman (Apr 25, 2015)

YOYO 02 said:


> Bonjour, j'ai le voyant DPF qui s'allume au bout de 10 minutes les codes defauts sont 480A / 481A / 4D00 mais la voiture roule tres bien. faut il changer le DPF?
> MERCI


Hello, I have the DPF light that lights up after 10 minutes the fault codes are 480A / 481A / 4D00 but the car is driving very well. Do I need to change the DPF?

Thanks


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## DI54 (Aug 7, 2017)

SPL15 Enjoy your new 35d.. Our 2016 X5d is at 130K miles and it drives great. Properly maintained, these cars can last many years of trouble free miles. In addition, I am amazed how durable the DPF's on BMW Diesel vehicles. My 2010 Jetta TDI almost had 300K and while the car is in perfect shape, however, I had to personally change (very cumbersome process to replace) the DPF at least 3 times; they're somehow prone to crack and as a result would clog the low EGR filter triggering the MIL.


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