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E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

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  #1  
Old 02-02-2011, 11:19 PM
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bluebee bluebee is offline
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I'm confused how to properly test for DISA valve proper operation on the BMW E39

I'm confused how to properly test the DISA valve on the E39.

Today, after seeing ForcedFirebird's pictures of the inside of a bent exhaust and pitted intake valves in the #3 cylinder due to the DISA (DIfferenzierte SAuganlage - "Differential Air Intake") flap failing ... and then moments later, reading of Ågent99's smog-test saga where the DISA valve seemed to have been the culprit ... and then seeing cambrian123456 post where in the process of cleaning the ICV, he notices his DISA valve is filthy ...

And, earlier this week, DominguesE30 asked the similar question of how to test the DISA valve (without much response).

I got to wondering how to "really" TEST the DISA valve in the BMW E39.

Doing the obligatory searching ... I find a confusing jumble of tests:
- These pictures show varnish buildup (presumably that's a visual test)
- This picture shows the flap missing (another visual test)
- Poolman gave a noise/performance DISA test here
- ventsyv added a DISA rattle test here (another noise test)
- Ågent99 alluded to a "smoke test" here (a visual test for vacuum leaks)
- szee1 alludes to the "resistance" of the DISA flap here
- dakarm also alludes to the "resistance" of the DISA flap here
- Lbert says to check the condition of the o-ring DISA gasket here
- uncmozo mentions specific codes thrown here that implicated the DISA valve
- This rebuild DISA article says codes will be your first sign of malfunctioning
- This related DISA article says you'll get a misfire if the o-ring leaks

But I see no real diagnostic tree for the DISA valve.

Maybe it's time to start one?

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  #2  
Old 02-03-2011, 10:08 AM
henkzilla henkzilla is offline
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Bluebee- I too was plagued by this scenario... I had been battling a pretty bad idle stumble, and I inspected my DISA to the best I understood and had ruled it out-and moved on. When I finally gave up and brought the car in to the mechanic (I thought it was a vacuum leak that I couldn't find) it turned out to be the DISA. The mechanic "bench tested" it somehow. The car is back in the shop today for some unrelated stuff but when I pick it up I'll try to ask him how exactly he tested it.
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  #3  
Old 02-03-2011, 11:36 AM
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doru doru is offline
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It will usually pull intermittent P0171 and P0174 codes (running too lean on bank 1 and 2) - like a vacuum leak. Keyword is intermittent - like once a week. If the interval starts getting shorter you're in trouble.. Also, the DISA starts making noise.
Pulling out the DISA, if the valve is sloppy (no resistance) - she's on the way out.
If you just pull it out to check it, you better have some replacement O-ring which you can source from e-bay seller jdm-auto. Linky.
That is if the DISA is still OK. No sense shelling out 200 bux (yet).


P.S.: for clarification: the first thing to go is the resistance of the flapper. More air gets sucked in - like unmetered air (that's why the codes start popping up). This combined with the noise (you have to open the hood and hear close to the intake manifold. A helper should rev the engine) is a dead giveaway. Doing a vacuum leak test (smoke test) will reveal nothing - pretty much pinpoint the culprit. Also some stumbling when you step on it.
This is all the info I could gather over different forums.
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Last edited by doru; 02-03-2011 at 11:51 AM.
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  #4  
Old 02-03-2011, 04:29 PM
poolman poolman is offline
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The way I was taught to test the part--with the engine running lean over and put your left ear on the part--if you hear it rattling and making racket--it's bad--if it's silent it's OK--Rajaie was the one who informed me of the test--
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  #5  
Old 03-14-2011, 08:28 AM
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bluebee bluebee is offline
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An ingenious proposal for testing the DISA valve is in this thread today:
- DISA Activation Fail

The mechanic proposed placing a white dot in the location shown below; then at the proper RPM, the dot should 'move' one way, and then at the next RPM cut point, it should move the other way (the theory goes).

According to RDL, (m54x5[1].pdf), those RPM points are:
  • below ~ 4000 RPM closed
  • above ~ 4000 RPM open
  • rest position, i.e. when removed - flap open
Reference: Pages 42 -44 of the attached document.
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  #6  
Old 09-03-2011, 06:53 PM
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For the record, this E46 thread today referred to the following DISA valve test video for the M54 engine (same engine as many E39s):
- E46 (1999 - 2006) > Bad DISA w/o codes?

.
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  #7  
Old 09-25-2011, 11:16 PM
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For the crosslinked record, today, this thread shows an important point:
- Bingo!! I may have solved the misfire and lean codes P0171, P0174, P0300

Not only is the DISA responsible for some misfires, but, it can ruin your engine if you don't check it every 100K miles or so.




- Why check the DISA at 85K miles to 90K miles or whenever the airbox is removed (1) (2) & how to repair a rattling DISA unit (1) (2) (3) & why the DIfferenzierte SAuganlage ("Differential Air Intake") valve flap breaks (1), sometimes with parts sucked into the intake manifold (1) (2) (3) (4) (5) (6) (7) (8) & how the disa valve o-ring fails (1) (2) & how it can cause all sorts of cold-engine rough idle problems (1) (2) & where to get just the DISA valve o-ring (1) & how the DISA valve operates (0) (1) (2) (3) (4) & an example of how a broken DISA valve can ruin your engine (1) & how to test DISA operation (1) (2) (3) (4).
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  #8  
Old 09-26-2011, 11:10 AM
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Quote:
Originally Posted by bluebee View Post
For the crosslinked record, today, this thread shows an important point:
Quote:
Originally Posted by bluebee View Post
- Bingo!! I may have solved the misfire and lean codes P0171, P0174, P0300

Not only is the DISA responsible for some misfires, but, it can ruin your engine if you don't check it every 100K miles or so.


I said it will pull those codes - Post #3. And I also raised awarness a while ago that at around 90 k miles the DISA is on the way out.....
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  #9  
Old 09-26-2011, 03:56 PM
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bluebee bluebee is offline
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Quote:
Originally Posted by doru View Post
I said it will pull those codes - Post #3. And I also raised awarness a while ago that at around 90 k miles the DISA is on the way out.....
I had forgotten who had warned us, and I thank you for doing so!

It would be nice if we work on a group buy for a decent deal, both ways, with one of the sponsors. I'm not sure how to go about setting that up.

As for testing the DISA, here's another reputed test, in vitro:
- Bingo!! I may have solved the misfire and lean codes P0171, P0174, P0300

Quote:
Originally Posted by teklord69 View Post
I saw a video somewhere on how to test the vaccum on the valve. Move the flapper to the closed position, then block the vacuum hole with your finger. Release the flapper and it should not open all the way. It will stop in the middle position and wont open fully until you let go of your finger.



There is another suggested DISA unit test procedure from this thread below:
- E39 (1997 - 2003) > Car was throwing codes....DISA valve!

Quote:
Originally Posted by uncmozo View Post
If you didn't want to remove the valve, there is a small odd-shaped cover that easily snaps off with a small screwdriver. It's on the bottom right of the rectangle that is the main body of the valve. If you pop the cover off, you can manually actuate the valve. I would guess you could actuate the valve with engine running, and diagnose if the flap is working or not. I found this out after trying to take the old valve apart.
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Last edited by bluebee; 09-29-2011 at 12:38 PM.
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  #10  
Old 09-29-2011, 12:24 PM
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bluebee bluebee is offline
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Since I have the following codes, I decided today to remove my DISA for a look:
  1. P1083,BMW 202, Fuel Control Limit Mixture Too Lean (Bank 1 Sensor 1)
  2. P1085,BMW 203, Fuel Control Limit Mixture Too Lean (Bank 2 Sensor 1)
  3. P0174,BMW 228, System Too Lean (Bank 2)
  4. P0171,BMW 227, System Too Lean (Bank 1)
To remove the DISA was easy.
  • I removed the electrical connector to the DISA
  • With a hinged socket set, I removed the lower T40 Torx bolt
  • I removed the upper T40 Torx bolt
  • I removed the DISA (pressing down on one vacuum wire to provide room)
  • NOTE: I did not remove ANYTHING else (no MAF, no hoses, no battery connection, no nothing)

The one thing I should have done beforehand is that I should have purchased an aftermarket M54 DISA o-ring:
- Where to get just the DISA valve o-ring (1)




I wanted to innervate the DISA electrical connection to see if it would operate at either 5 volts or 12 volts; but I figured I'd check here first.

Q: Does anyone know if a 6 volt/12 volt battery charger can be used to test the DISA valve electrical operation?
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  #11  
Old 09-29-2011, 01:05 PM
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bluebee bluebee is offline
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Quote:
Originally Posted by bluebee View Post
Q: Does anyone know if a 6 volt/12 volt battery charger can be used to test the DISA valve electrical operation?
It looks like the test is to use 12 volts (based on this thread):
- E39 (1997 - 2003) > DISA Activation Fail

- The 12 volt test
Quote:
Originally Posted by VitaminXX View Post
The mechanic applied an external 12V power source to activate the valve, the white mark did not move also. He told me my DISA is bad.
From that same thread, it looks like these are additional DISA diagnostic test procedures:

- The moving dot test
Quote:
Originally Posted by VitaminXX View Post
The mechanic ... marked a white point on the DISA valve... He told me normally when I start the engine up and step on the gas to let the RPM up to around 3000, the white mark should move to right accordingly since the DISA is regulating the air flow. However, as I stepped on the gas, the white point did not move to right.
- The unplug test
Quote:
Originally Posted by VitaminXX View Post
The mechanic unplug the DISA terminal, nothing happened.
- The GT1 test
Quote:
Originally Posted by VitaminXX View Post
When I got home, I used my GT1 to activate the DISA valve, it seems the white mark did not move either.
And, from post #10 of this thread, comes these two videos for testing purposes:
- X3 E83 (2004 - 2010) > CCV time, oh and DISA too.

- The rattling noise test
Quote:
Originally Posted by poolman View Post
the way to make the test is, with the engine at idle lay your left ear over on the disa. If you hear rattling and such inside the box,it's bad and needs replacing.
Quote:
Originally Posted by szee1 View Post
It appears that unplugging the DISA connection should stop the noise.That said, I am not sure that unplugging it always eliminates the noise. I have read that you can also place your ear on the DISA while the engine is running and verify if noise is coming from it. From what I can gather, the failure points can either be a loose valve on the shaft or a failure in the vacuum system which creates the noise. Mine was a loose shaft and I don't recall any noise from it.

This is a good link to show how the valve is connected to the vacuum actuator.


DISA noise video.
The autopsy test:
- E39 (1997 - 2003) > DISA Autopsy

The ribbed-o-ring test:
- E39 (1997 - 2003) > DISA 0 Ring


Last edited by bluebee; 10-02-2011 at 06:59 AM.
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  #12  
Old 10-10-2011, 09:04 AM
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bluebee bluebee is offline
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You can't test something until you know how it works normally.

To that end, this explanation helps with any voltage tests we may run:
- E39 (1997 - 2003) > DISA Autopsy

Quote:
Originally Posted by AnotherGeezer View Post
After much research I found this to be the best DISA operation description I could find.

"The disa valve has an outer seal (inside the manifold) and a diaphragm inside the valve itself. The valve is constantly fed 12 volts during normal throttle operation and then open circuits on higher RPM and throttle opening. This deenergises the coil which stops the manifold vacuum from reaching the diaphragm. The butterfly then springs open."
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  #13  
Old 04-04-2014, 12:07 PM
oz striker oz striker is offline
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Question

Hey guys I too am confused. I've been getting the check engine light and P0171 and P0174 codes, over the last 20-30k miles, with it gradually coming on more frequently. The light comes on sooner, the colder the weather, if temps are above 15 degrees although codes come up, the "check engine" light will not. the car appears to runs fine, except for in winter when temps go below 5-7 degrees C, and when until its fully warmed up, the idle bounces up and down a little when I come off the gas to a stop.



My peake tool gives me:

Table 19
E3 is O2 sensor adaptation limit Cyl # 1-3
E4 is O2 sensor adaptation limit Cyl # 4-6

Here's a video of my DISA, yes its long vid, but essentially the pin is fine, the flap doesn't rotate freely, and moves the piston towards the vacuum pot. BUT the vacuum pot doesn't appear to hold position at 45 degrees



I'm just surprised that all other aspects of my DISA after 122k miles appear fine and that its the vacuum pot that's the cause of my codes and rough idle in cold weather. Any other checks I can do? Might try the white dot test.

Additionally:
MAF has been cleaned
CCV system completely overhauled (this actually decreased the frequency of the codes and engine light coming especially in the warmer weather last summer. And I've been through whole install again to make sure everything was connected up right)
Minor valve cover gasket leak (oil consumption well under 1 litre per 1000 miles)
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  #14  
Old 08-15-2014, 08:43 AM
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bluebee bluebee is offline
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There is a mechanical test proposed in this thread:
- DISA rebuild cured my power dip (1)

See also this thest on my DISA valve:
> E39 (1997 - 2003) > Strange results from a simple test of the M54 DISA valve today
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Each repair should invariably add to our knowledge base by the process of inexorable incrementalism.
Your job, in return, is to read the suggested threads, where the best people will always add value to those threads, either by pictures or by descriptions, so the next person with the same problem stands on your shoulders.
See also: E39 Bestlinks & How to easily find what you need

Last edited by bluebee; 08-16-2014 at 12:02 PM.
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  #15  
Old 08-15-2014, 01:15 PM
gvelco gvelco is offline
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i put 12v directly on the connector,there was some spark with ticking sound but disa lever didnt move so??
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  #16  
Old 08-16-2014, 07:58 AM
gvelco gvelco is offline
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i've measured today connector and there was 12.4 volts.also tried another used disa and the same thing,plastic lever isnt moving.
should i clear codes(someone called it here adaptation) before connecting new disa unit?? or it is plug&play type?
price of new unit is 200$
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