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Recently my 2000 M5 has been going into limp mode after a couple miles, once it warms up. It produces about half the power but otherwise runs normally for the most part, with normal temperatures. It does it every time, and if I start it warm it goes into limp mode right away. It also has extra loud valve clatter for several seconds after starting, louder and longer than usual. Sometimes it has a very rough idle when warm and other times it's fine. It had a CPS go out a while back that I hadn't gotten around to replacing, so the SES light was already on from that (and the exhaust was louder than normal).

I took it to a local shop that ran the codes but did not know what to do to fix it and recommended taking it to the dealer.

Here are the codes:
72 - Exhaust camshaft VANOS position control, Cyl #5-8
8F - E-box fan
5D - AfterCat oxygen sensor aging, Cyl #5-8
07 - Intake camshaft position sensor, Cyl #1-4
B8 - Intake camshaft VANOS position control, Cyl #1-4
CD-D5 - Misfire during warm-up, all cylinders (all codes in this range)
95 - Misfire w/ empty fuel tank

I assume the limp mode is related to VANOS issues because of the codes and the valve clatter, but could the e-box fan problem cause limp mode? Or is it likely an unrelated problem?

I don't know what the deal with code 95 is, but I'm pretty sure these problems have nothing to do with an empty fuel tank. :)

I'm concerned that the dealer will want to replace both VANOS units, all the sensors, and more to fix the problem, and charge more than the car is worth. I did some searching here and found references to VANOS solenoid boards that may be repairable, to cleaning or replacing the solenoids and o-rings, and to a "Dr. Vanos" that can repair them. Based on these codes and symptoms, what is the most likely problem and how should I go about fixing it? I assume I will need to replace an O2 sensor, a CPS, and the E-box fan, but what about the VANOS? How big a DIY job would this stuff be, or should I find another shop that can handle it?

Thanks,
- Dave
 

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Resetting the codes and seeing which are "fresh" is step one. You can buy yourself a tool to read the error codes. That's easier and cheaper than visiting a shop.

Do not let anyone replace VANOS. They always want to, and it's never the right move.

You haven't mentioned mileage or which sensors have been replaced before. If none, then you are probably due for oxygen sensors (pre/post-CAT and/or MAFS) and CPS's. Note that you should replace them in pairs. The solenoid board DIY is also worth investigating, but more involved than replacing the sensors.

Those 2-10 sensors should be considered consumables in maintenance. You need to prioritize, and re-evaluate with a code reader. The clatter could be a chain tensioner. That and the ebox error have fixes in the DIY sticky, too.
 

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Discussion Starter #3
Thanks chowdah for the feedback.

The car has about 106K miles on it. It has had the VANOS units replaced under warranty, as well as at least one CPS and I think O2 sensors and MAFs as well. All of this was several years ago at 70-80K miles. I'd have to dig through the paperwork to be sure.

I was thinking about getting a USB reader instead of the simple and more expensive Peake reader.

For the USB adapter, which of these would be best?
Amazon.com: Loftek Interface USB OBD2 OBD II for BMW - INPA/ Ediabas - K+ DCAN: Automotive
Amazon.com : INPA K+CAN K+DCAN Car Diagnostic tool Cable OBD USB Interface for BMW R56 E87 E93 E70 : Vehicle Electronics : Car Electronics
INPA K+DCAN USB interface inpa compatible for BMW, k dcan Auto diagnostic cables - Newegg.com
Interface USB OBD2 II Inpa K + CAN Car Diagnostic Cable for BMW - Tmart.com

Other recommendations welcome - especially for US based suppliers that can ship quickly.

I found this 20 pin adapter (from multiple sources), but the detailed description says it's for Porsches even though the title says BMW. Do I need a different one?
http://www.amazon.com/Elandpower-S-EOLF-BMW20P-Connector-Diagnostic-Adapter/dp/B0054FJEDK

If I do get the Peake reader, is this the one I need for a 2000 M5?
Amazon.com: Peake Research R5/FCX 3 BMW Scan/Error Reset Tool 87-00: Automotive

Sorry for all the links and questions. I want to make sure I get the right thing the first time.

Thanks,
- Dave
 

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Do you know if you are running a factory tune or aftermarket tune. My old shark tune caused all misfiring codes. It might be a possible cause.
 

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Recently my 2000 M5 has been going into limp mode after a couple miles, once it warms up. It produces about half the power but otherwise runs normally for the most part, with normal temperatures. It does it every time, and if I start it warm it goes into limp mode right away. It also has extra loud valve clatter for several seconds after starting, louder and longer than usual. Sometimes it has a very rough idle when warm and other times it's fine. It had a CPS go out a while back that I hadn't gotten around to replacing, so the SES light was already on from that (and the exhaust was louder than normal).
Well, the first thing that jumps out at me is you have all the symptoms of a bad CPS, you know about it, but you haven't got around to fixing it (if I understand you correctly). I suggest that be the first thing you do. In fact, unless you know some are younger, you should replace all 4. They seem to last about 100k miles, and degrade quietly, undetected by the DME. So the one you have the code for is shot.

Here are the codes:
72 - Exhaust camshaft VANOS position control, Cyl #5-8
8F - E-box fan
5D - AfterCat oxygen sensor aging, Cyl #5-8
07 - Intake camshaft position sensor, Cyl #1-4
B8 - Intake camshaft VANOS position control, Cyl #1-4
CD-D5 - Misfire during warm-up, all cylinders (all codes in this range)
95 - Misfire w/ empty fuel tank

I assume the limp mode is related to VANOS issues because of the codes and the valve clatter, but could the e-box fan problem cause limp mode? Or is it likely an unrelated problem?
The e-box fan code doesn't bring in the light or cause limp mode, and people seem to live with it, but I wouldn't wait too long to fix it as it cools the DME and it must get pretty hot in there with no fan.

I did some searching here and found references to VANOS solenoid boards that may be repairable, to cleaning or replacing the solenoids and o-rings, and to a "Dr. Vanos" that can repair them. Based on these codes and symptoms, what is the most likely problem and how should I go about fixing it? I assume I will need to replace an O2 sensor, a CPS, and the E-box fan, but what about the VANOS? How big a DIY job would this stuff be, or should I find another shop that can handle it?

Thanks,
- Dave
I see the CPS code is for bank 1. But you also have a VANOS code for bank 2 (72). That may be a CPS on that side or it may be a board problem. The boards usually need mtce after 100K miles as well, so it might be a good time to pull the two boards and do the work explained on here in many threads and DIY's. Or you could send them to Dr VANOS. They have quite a good reputation.

That 5D code is unusual. Are you sure you read it correctly? If so, it certainly says the sensor has gone bad.
 

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Discussion Starter #6
DeafM5, I believe it's a factory tune. I bought the car used so I'm not 100% certain.

68FB, Once I get a code reader I'll reset the codes and see what comes back. I'll plan to replace the CPS it indicates, and possibly the rest of them. I will also look further into the DIY VANOS solenoid board inspection/cleaning/repair, and send them to Dr Vanos if I can't get them working properly. If the O2 sensor code comes back I'll replace that as well. Same with the E-box fan.

Thanks,
- Dave
 

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And the primary timing chain tensioner is so easy to fix my kid sister could do it. I'd replace that before starting the motor again (along with the sensor mentioned above).
 

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And the primary timing chain tensioner is so easy to fix my kid sister could do it. I'd replace that before starting the motor again (along with the sensor mentioned above).
Now you've hurt the feelings of the guy on here who cross-threaded it and had to buy a new timing cover.
 

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Discussion Starter #9 (Edited)
I got the Peake code reader and read the codes before resetting, getting 8F, 72, 07, B8, CD, CE, CF, DO, D1, D2, D5. That's not quite all the ones the shop got, but they said they did not reset it. Can some go away? Or maybe the guy I talked to didn't realize they reset it, although I think the SES light was on when I picked it up.

Anyway, after driving it some more and reading/resetting when codes came back, the following codes have come back:
72 - Exhaust camshaft VANOS position control, Cyl #5-8
07 - Intake camshaft position sensor, Cyl #1-4
B8 - Intake camshaft VANOS position control, Cyl #1-4
5D - AfterCat oxygen sensor aging, Cyl #5-8

So it looks like I definitely need to replace the intake CPS on bank 1, and the aft oxygen sensor for bank 2. Apparently for the VANOS codes either the associated CPS or the solenoid boards could be at fault. I think I'll also replace the exhaust CPS on bank 2, or maybe just do all 4. I'll also inspect/repair both VANOS solenoid boards.

It still goes into limp mode, but after resetting the codes it seems to take longer before it happens. It also seems to be down on power somewhat at times, but not as bad. Maybe it's all my imagination (aside from the obvious limp mode). I wish I had a way to measure it.

I noticed that the loud valve clatter on startup varies in intensity and duration when the engine has been off for a while whether warm or cold but is always there, but if I restart it shortly after shutting it off there is none. It was also real bad when I first started it after letting it sit for days before I got the reader. It must be related to oil draining away from the VANOS system and valves. If it's related to lubrication, will replacing sensors and repairing solenoid boards address it?

Has anyone had luck with aftermarket CPS or oxygen sensors? When searching I found some surprisingly cheap sensors that claim to work in this car, and a whole range of prices from there to full price BMW sensors. I have found threads here where people had bad luck with them, but has anyone had good experience with a specific brand/source aside from BMW?

Edit - I'll also look into the chain tensioner as mentioned above.

Thanks,
- Dave
 

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There are a few things that cause VANOS startup rattle and leaking solenoids is one of them so do the board mtce first and see if that fixes it.
 
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