# CBU repair update



## ChasR (Aug 29, 2012)

So the local dealership diagnosed my car with CBU after the SES light came on and the car exhibited a rough idle. It threw two injector codes and corresponding smooth running codes. I paid $2800 to "fix" the car. After driving the loaner three days, I got the car back, with the SA advising that it ran great. However when I stopped at the first traffic light, the rough idle resumed. 300 miles later the SES was back on, throwing 4AF5, zero quantity adaptation Injector 3 and the corresponding smooth running code 459x (i forget which). It goes in tomorrow feor service, running terribly, down on power, poor fuel economy, very rough idle. THe idle was so bad it felt like running on 3 cylinders. Anyway, I now have the following codes:
3EC0 camshaft sensor no signal
4AF5 zero quantity adaptation inj 3
4592 smooth running
4687 Throttle valve actuator
4CE8 Haven't found this one yet
4595 smooth running
4B05 zero quantity adaptation inj 4
4596 smooth running
4B26 zero quantity adaptation inj 6

So either the car is falling apart, or the mechanic didn't get it put back together correctly, I got scammed on the CBU repair, or all of the above.


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## F32Fleet (Jul 14, 2010)

ChasR said:


> So the local dealership diagnosed my car with CBU after the SES light came on and the car exhibited a rough idle. It threw two injector codes and corresponding smooth running codes. I paid $2800 to "fix" the car. After driving the loaner three days, I got the car back, with the SA advising that it ran great. However when I stopped at the first traffic light, the rough idle resumed. 300 miles later the SES was back on, throwing 4AF5, zero quantity adaptation Injector 3 and the corresponding smooth running code 459x (i forget which). It goes in tomorrow feor service, running terribly, down on power, poor fuel economy, very rough idle. THe idle was so bad it felt like running on 3 cylinders. Anyway, I now have the following codes:
> 3EC0 camshaft sensor no signal
> 4AF5 zero quantity adaptation inj 3
> 4592 smooth running
> ...


Nobody got scammed. The tech probably didn't put the injectors back in their original slots and or didn't reprogram them.


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## rmorin49 (Jan 7, 2007)

Another example of why BMW is not having much success with diesels in the US.

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## Flyingman (Sep 13, 2009)

Clearly. How often do you think a BMW Tech has actually taken apart a diesel????


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## n1das (Jul 22, 2013)

There may be something else going on with the engine that wasn't diagnosed and fixed earlier and the problem simply reared its ugly head again. CBU was probably a result of whatever the original problem is and not the actual cause.

Any visible smoke from the exhaust? With the engine running badly I would expect the engine to be making a TON of smoke. You probably won't see it due to the DPF "hiding" the smoke which also means the DPF would be getting sooted up real quick. Not too long ago back in the days before diesels required DPFs and were running on rotgut fuel, visible smoke was useful as a diagnostic tool. By paying attention to the amount of smoke, color of smoke, and the conditions when it was produced, you could get an idea of what was going on with the engine and know if it was normal or not. Now with DPF-equipped diesels the DPF does a good enough job of hiding smoke that in theory you could have a problem and not know it due to not seeing any warning signs (smoke!) until you have bigger problems (CBU, clogged DPF, etc.) later on.

Good luck.


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## Wannabe32 (Jul 2, 2014)

Which dealership did you go to? Did you get new injectors also? I've read about a number of problems with them as well.


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## Diesel Power (Oct 2, 2010)

There have been issues with injector 3 faults after CBU that requires a certain protocol or replacement of the DDE. The DDE had to be replaced In my 2011 335d after CBU to resolve the injector 3 problem.


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## Hoooper (Jun 17, 2013)

seems like most of the CBU repaired cars have either had injectors replaced during the repair or shortly there after.


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## ChasR (Aug 29, 2012)

n1das said:


> There may be something else going on with the engine that wasn't diagnosed and fixed earlier and the problem simply reared its ugly head again. CBU was probably a result of whatever the original problem is and not the actual cause.
> 
> Any visible smoke from the exhaust? With the engine running badly I would expect the engine to be making a TON of smoke. You probably won't see it due to the DPF "hiding" the smoke which also means the DPF would be getting sooted up real quick. Not too long ago back in the days before diesels required DPFs and were running on rotgut fuel, visible smoke was useful as a diagnostic tool. By paying attention to the amount of smoke, color of smoke, and the conditions when it was produced, you could get an idea of what was going on with the engine and know if it was normal or not. Now with DPF-equipped diesels the DPF does a good enough job of hiding smoke that in theory you could have a problem and not know it due to not seeing any warning signs (smoke!) until you have bigger problems (CBU, clogged DPF, etc.) later on.
> 
> Good luck.


No smoke, but more frequent regens.


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## ChasR (Aug 29, 2012)

Wannabe32 said:


> Which dealership did you go to? Did you get new injectors also? I've read about a number of problems with them as well.


I'm going to see how the dealership handles this before I name them (disclosure: I own stock in the dealership conglomerate). No new injectors were installed in the CBU cleanup.


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## need4speed (May 26, 2006)

BMW's current sales strategy for diesel's in the US seems to be Charge more, give less, have issues fixing what they broke and the wondering/complaining about how the US just won't buy diesels. Did no one ever tell BMW that diesel has a bad name in the US, they have to do it better, easier and cheaper than the gassers. Also unlike Europe mpg max isn't the only thing that matters in a diesel and the government makes it more expensive to own a diesel. N4S


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## ChasR (Aug 29, 2012)

BMWTurboDzl said:


> Nobody got scammed. The tech probably didn't put the injectors back in their original slots and or didn't reprogram them.


I have no doubt they did the work I paid for. I have doubts that they were addressing the real problem. When I took it in, knowing how many 335d have CBU, I was pretty sure they had the correct diagnosis. When I got the car back with no improvement in any aspect, I began to wonder if they know what they doing. Scammed is certainly the wrong word choice, as it implies intent to defraud, which is not the case.


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## Flyingman (Sep 13, 2009)

Just leave them with the car while you use their loaner until they can figure it out.:tsk::tsk::tsk:


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## n1das (Jul 22, 2013)

ChasR said:


> No smoke, but more frequent regens.


The more frequent regens means it's sooting a LOT. You would definitely see it as visible smoke if the car weren't equipped with a DPF. That says there's something else going on that's causing the smoke and later followed by CBU due to the smoke. The root cause of the smoke needs to be nailed down and fixed.

Is there any way to check injection timing? Retarded timing (late injection) will result in lots of smoke when under load, hard cold starts in winter, poor MPGs and performance.

Any restriction in the air intake path? Only OEM air filters should be used.

When was the fuel filter last changed? A fuel filter that's becoming restrictive can lead to retarded timing in some diesels that I'm familiar with.

Even if everything else is OK, an injector with a bad spray pattern can cause a LOT of smoke. Hopefully the injectors aren't hoofed.

Just offering up some ideas FWIW.

Good luck.


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## mefferso (Feb 26, 2014)

ChasR said:


> No smoke, but more frequent regens.


Just curious, how frequent did the regens become?


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## ChasR (Aug 29, 2012)

Every 250 miles compared to every 500 or so.

Somehow, they decided that replacing injector 4 would fix it. It didn't and they still have the car. I'm supposed to be able to get it back tomorrow. Seriously thinking of trading it in on a F30 335i Sportline I found on Autotrader. $4000+ in a month in repairs has rather soured me on BMW diesels. Lease one, maybe. Own one, never again. I'll probably wind up having to clear the codes to get it traded in.


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## ChasR (Aug 29, 2012)

Weeks later, after replacing the one injector, the car is running OK, with the exception of at least 3 regens per tank and the resultant poor fuel mileage. I did a dyno run on an older model dynojet and came up with 274.8 whp, down about 15-20 from where it should be. THe old dynojet couldn't get a torgue reading. Hand calculation using HP @ rpm gives 500 #' @ 2000 rpm.


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## pasing (May 11, 2011)

ChasR said:


> Weeks later, after replacing the one injector, the car is running OK, with the exception of at least 3 regens per tank and the resultant poor fuel mileage. I did a dyno run on an older model dynojet and came up with 274.8 whp, down about 15-20 from where it should be. THe old dynojet couldn't get a torgue reading. Hand calculation using HP @ rpm gives 500 #' @ 2000 rpm.


Just curious, how many miles do you have on your 335D?

Would this have been covered under the extended (platinum) warranty that BMW offers?

Thanks.


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## 335dwanted (Aug 1, 2014)

Chas, how are you tracking your regens? I have BMWhat and Torque apps but I don't see an easy way to see a regen.



ChasR said:


> Weeks later, after replacing the one injector, the car is running OK, with the exception of at least 3 regens per tank and the resultant poor fuel mileage. I did a dyno run on an older model dynojet and came up with 274.8 whp, down about 15-20 from where it should be. THe old dynojet couldn't get a torgue reading. Hand calculation using HP @ rpm gives 500 #' @ 2000 rpm.


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## ChasR (Aug 29, 2012)

You can watch the fuel mileage gauge on your commute. If it says 28 mpg where it normally says 36, it's doing a regen. If, when you park the car, the fan runs on and the car smells hot, it's doing a regen. People with good ears, on a smooth road, can hear the change in the engine note.

Edit: 93K miles


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