[biotite]

Last week I had a "Drivetrain Malfunction" error on my 2017 Xdrive 3.5 with 24,000 miles. The car drove normally, and the error didn't reappear after I turned the engine off and restarted. I took the car to the dealer yesterday they found:

1) Bad battery. I've seen that the a bad battery can trigger the drivetrain error, and had it replaced.

2) "Found boost control low pressure. As per test paln due to visible smoke in the smoke test we need to start with both air ducts coming from turbo to air filter box. Recommend replacing both ducts." Cost to do that would be $1,300.

I declined #2 since I didn't know the implications of the problem. What they proposed was the beginning of a test plan to fix the low pressure problem, and I didn't know the next steps, or how much they would cost. Also, I'll take it to an independent shop if it needs more work.

All of this was communicated to me in texts, and the authorization to do the work was a web page. I never talked to a human about this, and my call to my service manager went unanswered.

The car drives fine now.

What are the implications of low boost pressure? Will I have less power? Does it indicate a serious problem in the engine? Is it associated with the "drivetrain malfunction" error? And is this something that I need to get fixed sooner rather than later?

Thanks for your help and advice!

[slowblackx3f25]

Originally Posted by biotite

Last week I had a "Drivetrain Malfunction" error on my 2017 Xdrive 3.5 with 24,000 miles. The car drove normally, and the error didn't reappear after I turned the engine off and restarted. I took the car to the dealer yesterday they found:

1) Bad battery. I've seen that the a bad battery can trigger the drivetrain error, and had it replaced.

2) "Found boost control low pressure. As per test paln due to visible smoke in the smoke test we need to start with both air ducts coming from turbo to air filter box. Recommend replacing both ducts." Cost to do that would be $1,300.

I declined #2 since I didn't know the implications of the problem. What they proposed was the beginning of a test plan to fix the low pressure problem, and I didn't know the next steps, or how much they would cost. Also, I'll take it to an independent shop if it needs more work.

All of this was communicated to me in texts, and the authorization to do the work was a web page. I never talked to a human about this, and my call to my service manager went unanswered.

The car drives fine now.

What are the implications of low boost pressure? Will I have less power? Does it indicate a serious problem in the engine? Is it associated with the "drivetrain malfunction" error? And is this something that I need to get fixed sooner rather than later?

Thanks for your help and advice!

if your BMW is not under-warranty, take it to an independent EURO/BMW specialized shop...

but if you have money to spare and throw at a BMW dealership, go for it.
AND if you have BMW warranty on your BMW, take it to the dealership...

but since they are sending you a price quote, I think you don't have warranty...

take it to a BMW specialist or EURO specialized shop. My two cents.
I hope this helps.

[biotite]

Thanks, my X3 is out of warranty and I'll be taking it to the shop that maintained my Z3.

[mwat]

Very odd.
I'm told that dealers will change a battery before they do ANYTHING if they pull any sort of low voltage codes. Allegedly low/bad battery can cause a myriad of issues and they're told to do this as step 1 before anything else if these types of codes exist.

I agree with the 2nd poster however, get a second opinion from an Indy.

How much did the dealer charge you for the batter/reprogram?

[biotite]

The battery itself, with diagnosis and reregistering was $620.

[pungo]

Originally Posted by biotite

The battery itself, with diagnosis and reregistering was $620.

Could have purchased 3 batteries and a diag tool to register it.

[biotite]

That included the complete diagnosis on the car ($265). They even sent me a short video of a little bit of smoke around the turbo air ducts. Without any explanation, though, I don't know if it was smoke from the "smoke test" they ran, or what it means. Obviously, the mechanic thought that the low boost pressure was due to a crack in the ducts feeding the turbo, but there was no explanation of how serious (or not) the problem was.

[pungo]

Originally Posted by biotite

That included the complete diagnosis on the car ($265). They even sent me a short video of a little bit of smoke around the turbo air ducts. Without any explanation, though, I don't know if it was smoke from the "smoke test" they ran, or what it means. Obviously, the mechanic thought that the low boost pressure was due to a crack in the ducts feeding the turbo, but there was no explanation of how serious (or not) the problem was.

The charge pipe on these is a common failure since they're plastic so become brittle over time from heat and crack. Many times they blow off so there's zero boost. There are aftermarket replacement pipes made from aluminum which will never fail again. I don't know what your problem is with the low boost pressure, or if the smoke test proved the pipe(s) were leaking, but a leak after the turbo will cause reduced power.

[biotite]

Thank you!