CHECK ENGINE LIGHT IS ON
 

2003 X5 3.01 AWD
Check engine light is on.
I have replaced my DISA valve and also replaced the MAF.
Spark plugs are new, air filter is new, Fuel filter is new.
I am getting code P0175 Bank 1 System too lean
P0172 Bank 1 System too lean.
Any cluese what is causing these codes?

Most common cause is likely a cracked lower intake boot, but there are plenty of vacuum leak problem areas on these engines. Also be prepared to replace the CCV and hoses as well.

Smoke test is the quickest and easiest way to find the problem(s). Make sure you check both the intake and crankcase. Remove the oil fill cap and let the crankcase fill with smoke then put the cap back on.

See this video below, cheap fluid transfer pump under $10 at most auto parts stores, a few rubber gloves, rubber bands and cheap cigars.

https://www.youtube.com/watch?v=AsgB9eBl58I

As noted before smoke test is the best way to determine a leak that is producing a lean code.

Forgot to mention, keep your original MAF if you still have it. I would put it back on the vehicle.

Unless you purchased a Siemens/VDO MAF from a reliable source, if what you purchased was a no name or too cheap to be true, chances are it is an Asian counterfeit that may make matters worse.

I NEVER throw away a MAF, but I also rarely change them either. MAF's are replaced far too often when they are good. Unless you have Lean codes at highway cruise, chances are the original MAF was fine.

No code expert, but why not find a good Indie with good scanner/BMW menus and have him read your code(s)?

I had P0172, AZ read it generically, and then a good local Indie nailed it via a specific menu/sub menu and replaced the exhaust camshaft sensor...

Rather than throwing parts, fiddling with MAF/DISA, get it read and then chase the part(s) repair.
GL, mD

POINT OF ORDER
Lean codes are P0171 & P0174. The codes you gave are for Rich, not Lean.

P0170 & P0173 are Malfunction
P0171 & P0174 are Lean
P0172 & P0175 are Rich

Since there are specific codes for lean and rich, I assume that "malfunction," means that the fuel trim/control swings between rich and lean -- it is unstable enough to be wrong, but not consistently wrong to be one or the other.

Thanks for the input. You got it all wrong here. DISA and MAF was already replaced. Not because of this issue.

Miswrote...your orig post read like you had changed out MAF, et al, in the pursuit of extinguishing the CEL.

My thought was/is get the code(s) read with a real code reader with proper interpretation, and with that diagnosis an effective repair can be made.

Despite the misunderstanding, his advice to have the specific BMW codes read would be a great place to start. Those codes are thrown by so many causes... MAF, DISA, O2 sensors, CPS, vacuum leaks (most common), CCV, etc, etc.

If the SES/CEL/MIL is lit you really do not need a BMW specialized tool or software to read the codes.

OP did not mention what tool was used to read the codes and did not provide Freeze Frame date or Fuel Trim info.

Yes, in theory P0172/P0175 tend to be Rich codes, HOWEVER, there may be some typos and even if you study the Bentley manual closely there are some BWM codes that at least Bentley show pr translaste as BOTH Lean and Rich codes.

So I would guess the tool originally used likely output the codes in BMW 3 digit format and were incorrectly translated. Most modern vehicles do not run Rich as the vehicles ages and sensors and components age, usually the opposite.

I would be more than comfortable using a decent generic OBDII tool to gather the codes from this vehicle along with Freeze Frame and Fuel Trim data. Even a smart phone App like OBDFusion would be more than adequate to start with and it will give correct info because there is no translation from a BMW specialized code, the tool reads the OBDII PID's directly.