Service Engine Soon

[Tarheel]

I have a service engine soon light on. Took it to the shop and the mechanic removed and replaced variable valve Timing Solenoid, adjusted the camshaft solenoid, and added Archoil Friction Modifier.

The next day the warning light is back on. Mechanic says to drive it on a trip long enough to get the engine oil warmed up as stop and go driving doesn't do that. So I drive 120 miles round trip at speeds from 55-90mph with out stopping.

The light is back on! Ideas?

[pungo]

It could be a hundred things, without knowing the error code(s) it would be a wild guess what's wrong. Take it back to the shop and ask them to diagnose the error code(s). They should at least read the codes without charging you since they just did repairs and the light came back on.

[Tarheel]

Thanks Pungo!

[Finnegan]

I had the genius move of not fully clicking the gas-cap shut awhile back. That gave me a service engine soon light. Found my mistake and cleared the code.

As Pungo said it could be a ton of things, What codes did the mechanic pull when they scanned the ECU for errors? That can tell you a ton of things...like you didn't click your gas cap fully lol.

Good luck!

[racerbruce]

Originally Posted by Finnegan

I had the genius move of not fully clicking the gas-cap shut awhile back. That gave me a service engine soon light. Found my mistake and cleared the code.

As Pungo said it could be a ton of things, What codes did the mechanic pull when they scanned the ECU for errors? That can tell you a ton of things...like you didn't click your gas cap fully lol.

Good luck!

Thank you for the refreshing honesty in telling the story about the gas cap - it helps all of us.

[Efthreeoh]

So just to be clear, I'm assuming you have a Z4 3.0si Coupe with a N52.

So what the mechanic told you makes no sense, but maybe there is a translation situation between what he said to you and you posted here.

"mechanic removed and replaced variable valve Timing Solenoid, adjusted the camshaft solenoid, and added Archoil Friction Modifier"

So a bit of education. The variable valve timing solenoid is called a VANOS solenoid. There are two (2) on the N52 engine, one for the intake camshaft and one for the exhaust camshaft, but they are identical parts (i.e. same part number). The solenoids use oil pressure to operate the VANOS timing mechanism on the camshafts to allow the camshaft timing to vary based on engine load. The VANOS solenoids have variable orifices that adjust the flow of the engine oil. The engine computer (ECU) adjusts the orifices as required to meet camshaft timing needs based on engine loading.

The solenoids can get dirty and throw an SES light, or can wear to a point they no longer meet specification and require replacement. The proper procedure when a VANOS SES trouble code comes up is to swap the VANOS solenoids from intake to exhaust and vice versa to see if the SES trouble code follows the offending solenoid throwing the SES trouble code. The reason this procedure is followed is because the SES trouble code can also be related to the camshaft position sensor, which is located near the VANOS solenoid under neath the ledge of the cylinderhead (they are hard to see unless you look very closely). The camshaft position sensor is the feedback loop the ECU uses to adjust the VANOS solenoids. The maintenance procedure I practice is I remove the VANOS solenoids every 50,000 miles, clean them, then swap their positions. The theory I use is the VANOS solenoids are identical parts for both positions, but since one is intake and the other exhaust, they move differently to operate their respective camshaft positioning, so swapping them every 50,000 miles allows the solenoid not get used to a set of routine positions. It's just my theory, but I can say the VANOS solenoids didn't require replacement in my E90 325i until 306,000 miles (and just one went bad).

In front of the VANOS solenoids (speaking oil path flow-wise) are two small one-way pressure check valves that sit inside the cylinderhead on the exhaust side of the head near the front. It's rare, but they can clog up and restrict the proper flow of oil to the VANOS solenoid. Inspecting those check valves would be a last resort to diagnose a VANOS problem. The check valves have a small screen built into them, which can get sludge buildup over time. The N52 has been known to have a "camshaft bearing ledge" problem that can also throw a VANOS trouble code. This is also a rare situation. It's too long to explain here, but you can do and internet search on "N52 camshaft bearing ledge" for more information. That is an expensive fix because it requires digging into the cylinder head to correct. Again, it is a rare issue with the N52.

Then your mechanic said he "adjusted the camshaft solenoid", which makes no sense, because there is no "camshaft solenoid" (other than the two VANOS ones), and they can't be mechanically "adjusted". He may be speaking of the Valvetronic (electric) motor, which can only be "adjusted" by running a computer routine so it learns the limits of its mechanical positioning. A mechanic will run such a routine when he removes and replaces the Valvetronic motor. Valvetronic is another camshaft adjusting mechanism that acts as the engine throttle (it is different and separate in operation from the VANOS system).

I can't speak to the friction modifier. BMW recommends not adding any type of modifiers to the engine oil for the N52. I looked up the product and it is an oil treatment for diesel truck engines. I have over 850,000 combined miles covered over 4 BMWs (3 which I still have) and never used any oil additives, one car is over 350,000 miles, one went 256,000 before I sold it (last mileage I knew it had was 259,000), one has 185,000, and the last, just hit 92,000 (an N52 Z4) - all have (had) the original engines. Snake oil IMO.

Sorry for the long-winded post, but I'm getting to the point. So you haven't said how many miles are on your car, and what the maintenance schedule that has been followed, and what oil and filter has been used in the engine. Oil and filter type is important for the N52 because it is so dependent on proper lubrication system performance. Using an engine oil that meets BMW's LL-01 spec and using the original equipment manufacturer oil filter, a MANN HU-816, is key to trouble-free N52 service. To me it sounds like your mechanic is not well versed in BMWs, just my opinion based on what you've posted, so if he's not a BMW certified technician, I suggest taking the car to a BMW independent shop that knows the N52 well. If you want more help from Bimmer Post, it would be advantageous if you can find out what trouble code(s) are triggering the SES light. That's the first step in diagnosing problems. Being it is a SES light, that means it is emissions related, so the issue is related to the emissions-efficiency of the combustion process, which narrows down the problem. It is best to get the BMW trouble codes rather than the OBDII trouble codes. I say that because the BMW trouble codes will be more precise regarding what system is being problematic. So have the car scanned with a BMW scan tool to get the best information for diagnosing the problem.

Hope this helps.

[ryleighgulino12@gmail.com]

my service engine soon light came on and when i start the car it seems to be a bit shaky. any idea on what this could be ?

[pungo]

Originally Posted by ryleighgulino12@gmail.com

my service engine soon light came on and when i start the car it seems to be a bit shaky. any idea on what this could be ?

This post is worthless without error codes

Reference post #2 above from 3.5 years ago

[Efthreeoh]

Originally Posted by ryleighgulino12@gmail.com

my service engine soon light came on and when i start the car it seems to be a bit shaky. any idea on what this could be ?

As pungo has now stated twice in this thread, no one can help you with diagnosis without retrieving the trouble code that is activating the SES light.

This website is a great place to educate yourself on what the SES light means when it illuminates.

https://www.obdadvisor.com/most-popular-obd2-codes/

[wdb]

Yes but it only does it on Tuesdays when the moon is in its waxing phase, doesn't that help? Why can't you tell me what is wrong!!!1!!!!!!

[elerner61]

Originally Posted by ryleighgulino12@gmail.com

my service engine soon light came on and when i start the car it seems to be a bit shaky. any idea on what this could be ?

Since it's shaking while the car is not moving then it's definitely not the wheels or the driveshaft or the steering or the headlights. It must be the motor.

Welcome to Monday.