BMW E36 Blog

Cleaning E36 ICV (Idle Control Valve) . . . DIY!

23rd June 2007

Cleaning E36 ICV (Idle Control Valve) . . . DIY!

posted in Do It Yourself, Engine, Technical Info |

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Hi Guys,


Car hesitation and RPM bouncing are the most common problems between the BMW E36 cars. It seems that many cars have the problem and the problem is very hard to fix. I recall that even my previous E30 used to have the problem, but some how, the problem was solved. Maybe with something that I did and didn’t notice it fixed the problem.


Now my E36 318is is having the same symptoms and it gets very annoying especially when I turn my A/C on.


I started looking for a solution to this problem and it seems that cleaning the ICV (Idle Control Value) is one of the most obvious reasons for the problem, so I looked for a DIY about it and found one. The DIY is for M42 engines. I will be writing another post to fix same problem for the M50 engines. Please notice that I didn’t try this DIY myself yet, but I’m going to do it very soon.


Please notice that that cleaning the ICV will not always fix the problem, but it’s a very common reason, so if it didn’t totally solve your car’s problem, then you have other issues, but since the procedure is very simple, I guess everyone should start with it. Please follow the steps below and see if this fixes your car’s RPM bouncing problem. Enjoy 😉



Disclaimer: Use this info at your own risk!! I’m not responsible if this didn’t work for you.

This DIY / write-up will require the following tools/supplies:

Flashlight would be helpful.

11mm socket

Flathead screwdriver

Throttle body (TB) cleaner

OEM hoses if in need of replacement

Throttle body gasket and intake manifold gasket (not technically necessary, but a good idea)


It took me about an hour to remove, clean, and put back the ICV. Plus I let the hoses dry (while out of the car) for about 20 minutes on top of that.


First, start by opening the hood with the engine off and hopefully not too hot, as you will make contact with the block and the intake manifold.


You will take off the intake tube, shown below, by loosening the screws at the blue arrows, and pulling off the hose at the red arrow. Then pull the intake tube off completely.



Next, you remove the throttle body, by four 11mm bolts. The top two are shown with red arrows below. The bottom two are on the bottom of the TB, in the same position as the top two.



Move the throttle body off to the side, to gain access to the upper intake manifold, like this:



Next, we’ll disconnect the hose connecting the manifold to the ICV we wish to remove and clean. Behind the manifold, at the back of the engine bay, is the hose. Just twist it off, as shown by the red arrow.



Now it’s time to remove the upper intake manifold. Undo all 5 of the 11mm nuts attaching it to the lower manifold. The nut locations are highlighted below with red arrows. The nut in the rear of the engine bay is hard to get to, but a small 11mm socket and 1/4″ drive ratchet should get it out.



Next, carefully remove the manifold, by slowly lifting it up. I pried it off woodworker style using the backside of a hammer against the block. Be sure to remove it evenly though, lifting it up equally on all sides. Otherwise it will get stuck on the bolts on the manifold’s drivers side. It is easiest to place it as shown:



Now we have acces to the ICV. As shown below, it is attached with a rubber strap at the point shown with red arrows. The blue arrows indicate the electrical connection, which pulls of when you press down a wire clip. They also point to the hose connections, which you will also want to remove. Note the arrow on top of the ICV. It points TOWARDS the block. The part label with Bosch and the BMW part number written on it also face the front of the car. This is important. You want to put it back facing the correct direction.



Now, take the ICV and clean it. The image below shows the ports into which the tubes were plugged, and air flows, with a blue arrow. You’ll want to hit it with an old toothbrush and a gratuitous soaking with the TB cleaner. You may choose to clean the throttle body itself while at it with some paper towels and the cleaner.



Let everything dry, and clean off the hoses if you’d like. One of mine was cracked and therefore replaced, but washing the oil and grease off of them will help them last longer. Replace any that are cracked! They will make your idle worse and allow unfiltered air into the engine = bad. Be sure to let everything dry, especially items that were cleaned with water (hoses.) Installation is the reverse of removal. Be sure to connect ALL the hoses – double check!


Are you looking for more do it yourself procedures (DIY) ? I recommend the Bentley BMW 3 series service manual for you. I got it and I think it’s a gold mine for us -BMW E36 Owners-. If you didn’t grab your copy yet, get it right now! I’m sure you’ll find this book worth every penny you’ve paid for. Get the Bentley BMW 3 series service manual


Wait for more from BMW E36 Blog.


Best regards,

Tony Sticks.

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There are currently 133 responses to “Cleaning E36 ICV (Idle Control Valve) . . . DIY!”

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  1. 1 On September 29th, 2008, Vidma said:

    Yesterday I have changed LZ (new bosch), checked air temp sensor, coolant temp sensor, both are ok. Checked timing – ok. And still have jumping rpm on idle…
    Nothing left to check, so I’ll have to live with it…

  2. 2 On September 29th, 2008, ukfrog said:

    Yeah, join the club mate. I’ve been over the engine, the wires, the sensors, the injectors, the coils, the plugs, the air intake, the exhaust line. Still have the problem and no show on faults.
    Idle sucks, works fine one day, the next it’s not.
    My conclusion is that it’s irregular fault, maybe a miss fire on a coil from time to time.
    Like you, I’ll live with it, that is till I part exchange this for my next one. May not be a Bemmer this time, made me sick off the site of them this problem has.
    Looking at getting Audi, or something else not sure yet.
    But I’m surely not getting an other E36 in my life time.

    RIP E36

  3. 3 On September 29th, 2008, Andy said:

    I think you getting it wrong
    “# 100 On September 19th, 2008, Vidma said:
    Only its in the back of intake manifold. I don’t want to change this one, that used for speedometer…”

    The one in the back is not for speedometer, the one in the back is an airintake tempsensor, as it says in list, the speedometer does not have any component in the intake manifold.
    The speedometer gets its information from one of the sensors on the rear wheel.

  4. 4 On October 1st, 2008, Vidma said:

    Maybe my English is not very good. Speedometer temperature sensor is near coolant temp sensor, and I’m not interesting in it. I was talking about air and coolant sensors, but both are good.
    It gets that everything is good, but a problem is still there. Let it be… nothing left to check.

  5. 5 On October 10th, 2008, Joe said:

    Weeks ago, I posted a problem with rough idling in my 328i and today the problem was solved by installing a new set of spark plugs. Next time, I’ll do simple things like that before posting.

    I appreciate the feedback I got here and I’ll definitely keep this site bookmarked.


  6. 6 On October 10th, 2008, Andy said:

    Joe great that you solved it so easy, what brand was in the car before the change?
    What brand is the new sparcplugs?

    Do you see cracks in the old one?

  7. 7 On October 11th, 2008, Joe said:


    The old plugs were NGK BKR and had BMW printed on them. They had some dark, thick carbon deposits so I thought it was time to change them.

    I installed new NGK BKR6E V-Power plugs. I immediately noticed a difference in idling, acceleration, etc.

    I’m getting pretty handy with DIY car repairs. A year or so ago I did a minor repair of installing a new brake switch.

    Oh! I do have another problem. At times, my display shows a “Brake Light Circuit” problem when it seems I don’t have a problem with my brakes or brake lights. I had all new rotors, pads, etc. done about 2 years ago.

  8. 8 On October 16th, 2008, Vidma said:

    Latest new of my problem. I unplugged LZ heating relay, and my idle is steady now… almost steady. I was driving 4 days like this, and few times idle wanted to start jumping, but all time it gets steady. Or sometimes I can see very small idling jumps ~ 50 rpm. When I accelerate and leave engine to work on idle, it falls to ~500 rpm, and gets steady at normal ~650-700. it shows that not everything is good now, but…
    My LZ is new (same code), have changed 3 relays (used, same code), have changed DME.
    If it still shows small jumps, can it be only of that LZ signal is constant until gasses gets 300 C, and fuel mixture is richer, and that’s why idle is more stable? What do you think?
    I’ll get my car to a service to check wires of LZ and LZ relay to DME, but it will take a week, or 2 (lines).
    And now I cant get clear opinion about fuel consumption, as I was driving not a lot, but till now I cant say, that it will be more then before removing LZ relay.
    If fuel consumption will be the same, and no faults in wires will be founded, I think I’ll keep driving without relay, as this idle jumps got me mad, as I cant found a problem for about a year…

  9. 9 On October 25th, 2008, Rajiv said:

    hi, i followed the the step by step cleaning of icv and it solved my idiling problem compeletly ,furhrt i clean the air flow meter with carb clener and wd40….e36 now runs like a dream.

  10. 10 On October 26th, 2008, Tony Sticks said:

    @Rajiv: Congrats on fixing your idle problem.

  11. 11 On November 17th, 2008, Vidma said:

    There is video of my problem. If someone had same problem, and know how to fix it, pls advice.

  12. 12 On November 17th, 2008, Andy said:

    Widma can you record one again but turn the stereo off so i can listen to the engine, your problem looks identical to mine.

  13. 13 On November 18th, 2008, Vidma said:

    I’ll try, but its hard to catch a moment, when rpm is jumping, and I’m on normal road, as it usually starts when I’m going from a job on traffic jams…
    A sound is like I would push accelerator a bit. Its accelerating itself in short times.
    Anyway, I’ll try to film it today.

  14. 14 On November 21st, 2008, Vidma said:

    Tried to film, but no engine sound can be heard… my mobile is to weak…
    Andy – you had the same situation, that jumps stops when car stops, or you had jumps like mine, and rpm jumps were when car wasn’t moving? What was your solution of the problem?

  15. 15 On November 21st, 2008, Andy said:

    it jumps when puching clutch down or standing still in neutral.

    I haven’t seolved the problem yet.

  16. 16 On November 30th, 2008, Andy said:

    Widma how is it going with your problem?

    I toock my car for a spin today, to make the problem appear.
    But i only idles bad for about 20 sek after start.
    As usual this problem does not show up as often when it cold or wet outside.
    Im going to try it in a couple of days and when its warm and idling bad i’am going to pull the heating relay for lamda to see if it makes a instant difference.

    How expensive is the lamda heating realy to buy?

  17. 17 On December 1st, 2008, Vidma said:

    Andy – lambda relay shouldn’t do such effect, its for quicker heating, for ecologic purposes. That fuel mixture would be perfect asap. You’ll not get any difference, when you’ll pull out relay… but you may try, maybe heating component is bad…

    I got my car on diagnostics with carsoft 6.5 and got few errors. Maybe someone works with that program, and know what does these errors means?
    “Inst. Cluster dia. – Status ERROR -> read the error memory
    9 – Service period display (SIA)
    (This is if of that I didn’t reset my oil service)
    5 – Over supply on binder 15 is recognized

    11 – Colling liquid sensor voltage is not plausible
    (checked it on Saturday, got 5V – normal)
    12 – Oil temperature sensor voltage is not plausible

    Single diagnosis AIRCO – Status: ERROR
    34 Layering selector wheel
    Please check the connection of the white component plug PIN 21 to the layering selector wheel. There should be a voltage of approx. 5 volt on the layering selector wheel. If the connection is operative, the component must be replaced.”

  18. 18 On December 1st, 2008, Andy said:

    i have used carsoft i’ll try to figer out what it means.

  19. 19 On December 9th, 2008, Vidma said:

    I have changed my instrumental cluster and DME (from another M50b25tu), economizer don’t work anyway. I think it will be of wires.
    But got another news too. When I’m starting engine, rpm needle jumps for 1 time – as per manual, if needle jumps on start, then ignition is ok. And my rpm needle don’t get higher then ~1200 rpm on start (usually it gets as good start, of cold engine). Another thing is that I don’t have strong rpm jumps as previous, it became only 50-150 rpm. Engine response to acceleration on cold engine became better. Now I’ll driver for a few days to look for fuel consumption.
    I’ll inform you, what it will be.
    And got this whistling sound on acceleration, as it was on b20tu when it was driving fine 🙂
    p.s. DME was changed on Friday morning, so adaptation is over. Got a trip on weekend and for 120 km/h for 200 km I got ~25ltr, on way back 110 km//h for 200 km I got ~15ltr… interesting thing.

  20. 20 On May 10th, 2009, John said:

    Getting at the ICV in the M50 can be a royal pain….its located UNDER the intake manifold and unless you can tiny hands and wrists its next to impossible to reinstall properly without removing the manifold. Getting it out isn’t so bad, but good luck hooking up the hoses underneath and the clip they connect to.

    From past experience here’s what I know to check on these cars for hesitation and rough idle.

    1. ICV, cleaning it does help

    2. Check for intake leaks, although you’ll probably have some pretty bad surging if this is the problem

    3. The clip under the intake manifold where the ICV connects to, it can sometimes pop out or break. I epoxied mine in because I have a supercharger and it litterally shot it out across the engine bay one day under boost 🙂

    4. The MAF (Mass Airflow Sensor). This can either get dirty and need cleaning, especially the contacts on the connector, or, like what happend to me, a wire broke near the connector from age I think.

    5. Your intake boot has a hole in it….yeah this happens unfortunately, especially next to the ribs on the rubber. I think oil fumes in the engine bay eventually weaken the rubber..

    6. Vacuum Leak. If you have a vacuum gauge or boost gauge with vac on it, you can see if your car is at about 18-21psi at idle. (I ”think” this is the number, but please correct me if i’m wrong). If you don’t have a gauge then while the engine grab a propane torch and just turn on the propane a little bit, but don’t ignite it. Run the nozzle up and down all your lines and alone the intake parts as well. If the engine surges or changes idle while going over a certain spot, thats likely where the leak is.

    7. Your o2 sensor……I would leave this assumption to the very end because I can tell you for certain that the car does NOT use the sensor until the engine is at operating temperature. So if you have problems after you’ve just started up the car then its almost definitely not the o2 sensor. The car will run like complete crud if the sensor had an issue anyway, since it will default to using the MAF sensor only and the maps in the motronic ecu can only do so much to correct the a/f ratio

  21. 21 On May 11th, 2009, Lerato said:


    I have a problem with my E46 318i 2000 model, it overheats after about 20KM and when i open it in the front the water horses are so big.. they look like they will burst anytime. most of the parts are new (thermostat, radiator, “head is been cjecked for cracks”, water pump, V-belt); the only thing that i noticed that seem not to work properly is the crankshaft position sensor(pulse generator), can this cause the overheating? oh! and when the engine is running and switching it off, there is sound of air(pressured air) coming out but i cannot see where but its like coming from the back of the engine. it’s like there is some air coming in the engine at place where it’s not supposed to… please help


  22. 22 On May 18th, 2009, Vidma said:

    Lerato – maybe your radiator cap (its valve) is broken, and not working as should… it should hold ~2bar of pressure.
    And you can to try to do a “cooling system, bleeding”. Maybe there is air in the system.
    Have you tried to stop fan coupling on hot engine? Try it with scrolled paper. If it stops – its bad, if it don’t stop easily, then its ok.
    But I would check the cap of the radiator at first.

    Engine vacuum don’t have anything with cooling system…

  23. 23 On September 20th, 2010, Jake said:

    Hi Guys,

    Been reading your posts above and think that they will help as my car has recently started showing the same symptoms, the electrics in the car are also surging with the idle though? I’m not sure if this is an indication of a larger problem? For example after the car has been running for a while it gets a rough idle as mentioned above, if i have my lights on at the same time the head lights and guage back lights dim and brighten with the rise and fall of the rpm. Any ideas?

    Its a 95 318i running the m43b18,



  24. 24 On November 2nd, 2010, Jerry said:

    Jake, I would start with charging system.

  25. 25 On November 2nd, 2010, Jerry said:

    Mine is 92 318i E36. I had problems with rough idle, stall and hard start (cold hot and warm). Engine code 1215 (MAF). Checked vacumm hoses, battery, charging system, filters and everything was fine. Last weekend I took off the ICV without taking off the intake and throttle body. Cleaned it (brake clean), and cleaned the MAF and throttle. Now, it starts right away and no more rough idle, stall or hard start. Re-hooked the battery to clear up the code. It runs great! Thank you for your DIY post Tony!

  26. 26 On November 16th, 2010, Martin said:

    I would like to ask you one question. Should ICV somehow react to ignition or not? Mine does absolutely nothing, doesn’t matter ignition is on or off.
    The car is 93 318is M42B18. Month ago I had problem that after cold start it was idling way too high (~3000rpm). But that problem vanished, now there is only one issue: when I change to neutral gear, revs drop to ~500 then rise to normal ~800 and stay there.

  27. 27 On November 17th, 2010, Rob said:

    Hi, I have a 97 m3 evolution and was wondering if could tell me a easy quicker way of cleaning the icv as on my evo I have 6 throttle bodies and they are not easy to remove as you can imagine. Espically the back two near the bulk head.

    Reason for wanting to do it is that my revs drop to 500k occasionally instead of the standard 600 and on occasionion sit at 800.
    This came about after I cleaned my accelerator cable and took of my inlet and cleaned maf sensor!

    Asinine welcome

  28. 28 On July 26th, 2011, ray said:

    I have a 318 96 and have this whistle sound only when accelerate any idea what it could be it is not a turbo. cant hear nothing at idle.thanks

  29. 29 On August 21st, 2011, Richard said:

    Can you indicate me on how to clean the idle control valve on a 1997 318is with a M44 engine? As I can see on the photos here on your article the idle control valve are in different locations and have a totally different shape. On the M44 the idle control valve is located on the throttle body very easy to access, but seems the parts are different I would need the right info to clean it up
    Thank you for this nice write-up and hope you have an answer to my inquiry
    Again thanks

  30. 30 On June 30th, 2012, Flavio said:

    Carsoft 6.5

    12 – Oil temperature sensor voltage is not plausible

    Same here in my BMW 328i 1996 coupe.
    I don’t know where this sensor is in my motor.?
    Carsoft is giving this error eveytime.
    I clean up the error but it goes at hte time i turn the key on.

  31. 31 On July 1st, 2012, Richard said:

    Any comments on how to clean a ICV for a 1997 BMW E36 with a M44 (M44b19) engine. Thank you…

  32. 32 On September 22nd, 2012, jay said:

    Please help.Can I clean icv with petrol?.

  33. 33 On October 1st, 2012, Andy said:

    I would not clean it with petrol.

    Use carburator cleaner or breake cleaner.