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All i have a 2001 M5 with nearly 90,000 and the stinking check engine light has been on. i thought at first it was a secondary air problem i.e. carbon build up and spoke with Matt at powerchip who was helpful, and determined that was not the case. i took it to my mechanic today and got the folowing codes:
73 Air mass flow, which i understand is easily replaced
144 and 145 o2 bank 1 and 2 sensors, also easily replaced
178 and 179 Catalytic converter, needs new Kats as suggested by Matt

i have a good mechanic that deal with BMW, and Porches, but dont think they work on many M5s. do you all know of any good shop that i can take in Atlanta or surroundign area, that will be familiar with turning the check engine light off, with the least amount of money.

any suggestions, or how tos on doing it at my garage would be greatly appreciated.
 

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Welcome!

Step one: Read this, http://www.m5board.com/vbulletin/e3...34-e39-m5-frequently-asked-questions-faq.html

Step two: After reading through that, if you still have questions, fire away.

I'd say, at a glance, that your pre-cat O2 sensors need to be changed (there are two pair, pre- and post-cat) on each side. Usually, it's the pre-cats that go bad.

I'm not familiar with those codes, but assume they are OBD. In the FAQ are multiple entries on Peake. Read over those and see to getting you one of those readers if you intend to work on or diagnose your car yourself.

I'm not local to your area, so cannot recommend any shops. I'm sure someone else will chime in, though.
 

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Get a Peake. Reset and see what comes back. MAFS' underperformance can be tested/confirmed (read the FAQ). Ignore the cats error until you deal with other upstream O2 sensors first; it can be a false positive. These sensors are consumables. When was the last time they were replaced?
 

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If you listen to nothing else, heed this: DO NOT replace your cats until you've replaced your MAFs and your O2 sensors...AND cleared all codes...AND had the dme adapt to the new components.

IF you still get 'bad cats', take it to a shop to do diagnsitcs, in particular the air-fuel mixture.

You simply cannot diagnose cats with other bad components. If your fuel is whacked out the car will trip cat codes.

As far as how to: If you can use a pliers and screwdriver you can change your MAF. If you can jack up a car and use an open end wrench you can do the O2s (I once did it by driving up on a tall curb and sliding under...)

GL

A
 

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pm sent :)
 

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If you listen to nothing else, heed this: DO NOT replace your cats until you've replaced your MAFs and your O2 sensors...AND cleared all codes...AND had the dme adapt to the new components.

IF you still get 'bad cats', take it to a shop to do diagnsitcs, in particular the air-fuel mixture.

You simply cannot diagnose cats with other bad components. If your fuel is whacked out the car will trip cat codes.

As far as how to: If you can use a pliers and screwdriver you can change your MAF. If you can jack up a car and use an open end wrench you can do the O2s (I once did it by driving up on a tall curb and sliding under...)

GL

A
+1 on This...and for heaven's sake invest in a Peake reader or equivalent. I've used my (generic) code reader dozens of times over the years. I cringe at the thought of having to take my car somewhere every time one of my fleet lit an SES light.
 

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For the shop recommendation, go to Harrison Motorsports. The owner has an M5 and they do high quality work.
 

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fda with 90k on the clock you can easily justify replacing your MAFs, all 4 O2 sensors, and spark plugs without it being a case of 'throwing parts' at your car hoping to eliminate codes.
Bosch's website even states 100k as the 'check/replace' interval on O2's. Any O2 I might add...not just pre-cat ones. To me that just translates to replace.
BMW says 100k on spark plugs to which I say bull****. If you have no records to the contrary yours are about 50k overdue.
MAFs degrade over time due to contamination buildup. Cleaning them is generally a temporary fix at best.

Check Amazon.com for all parts (just use OEM equivalent...don't try and get fancy) except the MAFs. For them head over to Bimmerzone.com.

And while you wait for all of those parts to arrive take a quick drive over to AutoZone for two new air filters if yours have more than 10-12k on them. :M5thumbs:

I wouldn't be a bit surprised if one or a combo of these parts solved your SES light. Even if they don't your car will be much peppier I'm sure.
 
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