well as most of you know I just got my M5 yesterday and today while doing some "Spirited Driving" the service engine soon light came on so we went back to my buddys house and got his OBDII code reader and pulled this code PO430 this is "catalyst efficiency below threshold" and we cleared it then when I took my other buddy back to his house on the way back the light came on again for the same thing it didnt do it to me much yesterday but I didnt open it up as much and both times it has happened I was going pretty quick, is there a chance of it going into failsafe mode if the service engine soon light stays on for while? we cleared it again and im going to take it easy to see what happens.
Now, step 1: Get a Peake code reader. This will give you the specific BMW codes that you need. Generic OBDII readers are okay, but they are generic.
I do not believe that driving with the SES light on for a length of time will trigger fail-safe mode, but some conditions of the system will. Those conditions may or may not be related to the catalyst efficiency code you pulled. That's why it's important to get the Peake reader and find out what is going on. I believe you can find a link to the Peake reader in the FAQ thread.
If you have read any of these posts before buying your M5, you would have seen the following statement regarding what to look out for when buying a used M5:
"Pick the car that has been carefully maintained over the one with low mileage."
Why in the M5 world would you run the risk of shortening the life of your new (used) M5, by ignoring an SES light? I won't even comment on the environmental pollution you might be contributing to.
FIX IT or GET IT FIXED.
(And, yes, I know they can sometimes be benign, but why risk it?)
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"The greatest obstacle to discovery is not ignorance; it is the illusion of knowledge."
If the only code you have is cat efficiency, you won't hurt the car, nor should it go into limp home mode. That mode is generally reserved for misfires and other maladies that can actually damage the cats (i.e. too much unburt fuel)
Cat efficiency codes can be of course due to a failing catalyst, O2 sensors etc.
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Mike
91 M5 Alpine White II, Silver Gray 3/90 production
17x8/17x9 M system with PS2, 20mm touring roll bar; Ground Control Coilovers; EAT Chip, CD43; bmw/nardi blackline steering wheel, 3.8 Cam Gears
08 535i / 6 speed
Space Gray; Gray; Sport/Premium/Nav
00 M5 Ti Silver; Imola/black sportiv --Sold
Engine:
Supersprint Headers, Dinan CAI kit and MAFS, Throttle Bodies, Cams, Ported heads, Exhaust, Custom dinan software, Evosport Pullies, Dinan clutch and lightened flywheel; Ignition solutions plasma coils
Suspension:
Dinan Stage 3 with front and rear Strut Tower Braces, Beastpower Sway bar brackets, Dinan Wheels with 275/285 PilotSport, X5 Thrust arm bushings, Stoptech 355mm 4 piston front, 355mm 2 piston rear brake kit, Dinan 3.45 diff
Interior/Misc:
Eurodash, updated steering wheel, Bluetooth retrofit, Sirius Retrofit, hardwired V1, Widescreen Mk4 nav, M audio retrofit, Ice Link, BSW Stage 1 speaker upgrade, bmw towbar
Mottati is correct, more than likely it is a rear O2 sensors throwing the code as they are the ones that check the cat for efficiency, if they are good then it wold be the cat. Front O2 control fuel air ratio.
If you have stock exhaust, then to the extent you haven't smelled rotten eggs or heard a rattle in the cats, you should guard against cooking your cats. That danger is possible with any chronic rich condition from the likes of: upstream oxygen sensors reading wrong, thermostat being stuck open, fuel pressure being off, etc.
You got an SES the day after buying the car? Well...at least you know the former owner was smart enough to clear it before your test drive/purchase.
If you're lucky it is one/both of the post cat sensors failing and that's that. But bear in mind there's a chance a dying front O2 sensor may be the cause of this code if the front and rear O2's are seeing the same #'s the DME might think cats aren't doing they're job...just a guess really.
If you're unlucky one/both of your CATS is failed. Lets not think about that...yet.
If you're partially lucky your motor is just running poorly enough to keep the cats from being able to clean up the mess properly.
If I were you'd I'd concentrate on a "tune-up" first to make sure #3 isn't the root cause.
Air filters and spark plugs for a start unless you KNOW they are knew via PAPERWORK not former owners word. Also a fuel filter as well. Bad injector spray patterns from low fuel pressure could be a contributing factor to bad cylinder performance. And FWIW new pre-cat O2 sensors wouldn't kill you either. There's even a recent thread about them and their positive effects. I'd also use the "secret menu" to do the thermostat test to ensure my motor wasn't running cold...and therefore too rich. It is winter after all!
You've just bought a used car. Without P-R-O-O-F of tune-up work assume nothing has been done. Without proof you most likely need:
Oil and filter
Spark plugs
Air filters
Pre-cat O2 sensors
Fuel filter
If you still have codes after that THEN I'd change the post-cat O2's. But that's just me.
Good luck!
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Members:
If you want your oil pan repaired (see http://www.m5board.com/vbulletin/e39...rain-plug.html) instead of buying a new one or attempting the repair yourself PM me and we'll work something out. Thinking $60 profit is worth it. You pay all shipping of course. At the moment I have four remaining Timesert inserts looking for homes. If the demand is there I'll keep doing them. If not the tool goes on eBay minus one insert.
Last edited by TMcNasty; 7th January 2009 at 21:39.
i know the fuel filter has been replaced and I have recieved a 2 inch stack of papers of everything done to the car so its not just owners word I got it on paper, it does have a Dinan exhaust, I am gonna replace the O2 sensors and if that doesnt work the cats are getting deleted mostlikey and being replaced with straight pipes
i know the fuel filter has been replaced and I have recieved a 2 inch stack of papers of everything done to the car so its not just owners word I got it on paper, it does have a Dinan exhaust, I am gonna replace the O2 sensors and if that doesnt work the cats are getting deleted mostlikey and being replaced with straight pipes
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