My Engine Malfunction - Reduced Power Story...

[Maranello055]

I was on a trip to NC from Pittsburgh 2 weeks ago. On the way back from Charlotte roughly in Virginia, I received a Engine Malfunction - Reduced Power message on my dash. We were roughly 360ish miles from home on a Sunday with my wife and 10 month old son.

We stopped a few times in hopes that on a restart the light would go away. Of course it didn't. So we ended up limping home all the way.

We take the car to the dealership and at first they reprogrammed the ECU and all the modules in the car to the latest DME software. ( I personally didn't think this would solve this issue) But I went along with it. The dealership test drove the X5 and called me and said it was fixed!

I pick up the vehicle, pay the $255 for the program and start driving home. As soon as I get on the on-ramp to the highway... guess what - Engine Malfunction - Reduced Power. So i drive it right back to BMW and jump right back in the same loaner!

It takes a few days at BMW to run through their test plan and they notice that -

CLIENT STATES CHECK ENGINE LIGHT IS ON
FAULT FOR BOOST PRESSURE PLAUSIBILITY TOO LOW .
WORKED THROUGH TEST PLAN AND COMPLETED ALL CHECKS
INCLUDING MANUALLY APPLYING VACUUM TO WASTE GATE ACTUATOR
AND FOUND NO CAUSE FOR BOOST PRESSURE ISSUE. CONTINUED
TEST PLAN WITH RUNNING TURBO SELF TEST WHICH ABORTS.
FOUND WHEN ENGINE IS HOT PRESSURE CONVERTER IS
MALFUNCTIONING AND SUPPLYING CORRECT VACUUM TO WASTE GATE
ACTUATOR. ACTUATOR WORKED CORRECTLY WHEN TESTED EARLIER
IN TEST PLAN INDICATING A HEAT SOAK ISSUE WITH COMPONENT.
REPLACED PRESSURE CONVERTER FOR WASTE GATE. CLEARED FAULT
MEMORY AND ROAD TESTED 3 MILES OK. HAD DRIVEN EXTENSIVELY
TO VERIFY REPAIR , NO MALFUNCTION OCCURRED IN OVER 30
MILES.

11-74-7-626-351 PRESSURE CONVERTER (Pneumatic Wastegate Actuator)


So they road-tested the X5 for 30 miles and the light has not come back on.

I pick the car up later today! Lets hope that this fixes the issue!

I figured I'd write this up if anyone has this same issue and wants to replace the part themselves instead of the dealership.

[mirob]

Very good info! Do you mind re-posting into this thread? We've been trying to diagnose this issue since the beginning of time.

http://www.xbimmers.com/forums/showthread.php?t=1260684

[badge1]

Looking forward to hearing the results! This could be very good info for those who cannot solve this issue.

[Maranello055]

Going to pick it up in about 30... will report back tonight!

[badge1]

So??

[Maranello055]

So I drove the car for roughly 150 miles this weekend... FIXED!~

No check engine lights, performance is back. I'll of course continue to monitor this but it looks like it is solved!

Thank the lord!

[badge1]

Awesome - glad to hear it!

[heatmizr]

HOW do you keep your garage and countertop so.... empty?!

[m5james]

I didn't check the X5M vs the 550, but it's safe to assume the 550 has two of them as well. At $110 each on eBay, I'm going to clean them before replacing them.

Thanks for another piece to the puzzle.

[Maranello055]

Originally Posted by heatmizr

HOW do you keep your garage and countertop so.... empty?!

Haha its only 3 months old... Slowwwwly finishing it... Thats 13 feet of Granite Countertops in the back!

[F06msportmia]

Great write up! I just had this happen 2 weeks ago and couldn't figure out why.

[F06msportmia]

For DIY'er the part is not that expensive:

[F06msportmia]

Originally Posted by e70msportmia

For DIY'er the part is not that expensive:

See part cost;

[Maranello055]

I had the dealership do the work, so I'm not sure the exact installation process. I'm sure I could of done it but was in a time crunch!

Also - roughly 300 miles and no CEL's!

[m5james]

Bump for update as I've got my car apart trying to replace those sensors.

[Maranello055]

No issues yet! Works perfectly. This at least solved my problem. Hopefully its the same issue you are having! I even put the BMS tune on my car about 200 miles ago after it was fixed.

[m5james]

Sounds good...both sensors are on the same bracket and a bitch to access, but I'm still plugging away and replacing all the vacuum lines while I'm at it.

[Mybimmerbrain]

Originally Posted by m5james

Sounds good...both sensors are on the same bracket and a bitch to access, but I'm still plugging away and replacing all the vacuum lines while I'm at it.

Respect! Not a easy repair. You will finish for sure. Good idea replacing vacuum lines too.

[Maranello055]

Let me know how that all goes! Hopefully it fixes it...

[Revnato]

Originally Posted by m5james

Sounds good...both sensors are on the same bracket and a bitch to access, but I'm still plugging away and replacing all the vacuum lines while I'm at it.

I'm willing to bet once you replace all those vacuum lines you'll fix the issue

[m5james]

The charge pipe lines were fairly easy, and even though I had a torn hose, that didn't solve the issue. The vacuum lines on the backside of the engine are easy to access, it's the 4 lines going from the sensors to the wategates and vacuum canisters that have the hardest routing. It looks easy in the realoem pics, as does the far right and far left PCV/CCV lines (which I need to remove before being able to do the catch can setup) that suck to access. I've been using my 4 day weekend to spend with family and naturally caught a cold, but I need to get it done since driving the convertible in the rain isn't nearly as much fun as the X5M :-)

[m5james]

Pretty confident I fixed my issue. I've posted a nice lengthy reply on the other thread since I've diluted this one long enough :-)

http://www.xbimmers.com/forums/showthread.php?t=1260684