[spadilla7]

Hello, everyone.

I have searched this engine code, and there is really no information addressing this particular issue. Perhaps I am not using a good search terminology, but any help would be appreciated. I am using the Carly App and bluetooth dongle on my car.

2011 335d, 70k miles.

004b81: Engine/Motor Exhaust gas re-circulation rate control, deviation exhaust gas re-circulation rate control error while Kat heating

This is the only code I get that throws a CEL and the car goes into limp mode. When it happens, it always happens in low load situations like running with cruise control on the hwy at 80 mph/2k rpms or sitting at a light or pulling away from a stop sign at a slow rate. Once I drop below the 80mph/2k and after a minute or two, the CEL goes out on it's own, and the car returns to normal driving.

I have replaced the EGR valve, and I replaced the EGT sensor on the EGR cooler. I also replaced the EGT sensor before the DPF due to a different issue I had earlier in the year.

Possible DPF clogged? SCR Clogged? Cat is clogged? It sounds like, and I could be wrong, that there is a restriction of some sort causing the EGT's to climb, then the car goes into limp mode and then returns to normal once the EGT's are back in line.

Or is there another EGT sensor that may be bad and in need of replacing.?

Thanks for any help!

[Torqu3]

When you say you replaced the EGR, does that mean EGR cooler, or EGR valve?

[spadilla7]

Originally Posted by Torqu3

When you say you replaced the EGR, does that mean EGR cooler, or EGR valve?

Sorry, replaced the EGR valve, and a couple of the EGT sensors. I had the original on the car until about 1 month ago. This code has plagued me for a while now, say 6 mths or so.

[rkstar9]

Keep in mind there is a high pressure egr and a low pressure egr. The code is not telling you which one.

did you check the old egr valve to see if it was working?

I would get Rheingold and run the suggested test schedule for that code to see what parts might be compromised. Im guessing it's gonna suggest a functionality check of both egr valves.
and if they are not moving visually the next step is to test with a multi meter if they are getting the signal to open.

Same thing with the sensors you can run a test to see the temperatures are within range. I would not replace any more parts without diagnosing a bit more.

At this point could be too many different things causing the CEL

[robnitro]

On 335d there is no low pressure egr, that is only on the x5 35d.

What controls the egr cooler is a solenoid with vac lines on top, which move a vac actuator at the bottom of the egr cooler left side where it diverts the exhaust gas either through the cooler or bypasses it. Feel below the egr cooler left side for it while running whatever egr cooler test you can find in rheingold. It should move when it cycles the cooler valve.
At the top right exiting the rectangle part of cooler you see a sensor probe, which reports egr gas temperature. Again Rheingold might be able to check that, post your results of testing.

I assume rheingold will cycle the bypass valve to see if the egr temperature changes... If not, that vac actuated valve may have a problem with vacuun or the solenoid/connection bad, or actuator spring broken.

[ingenieur]

EGR rate deviation is usually due to measured air mass outside of the calculated threshold. These faults do occur more frequently on the X5 due to the higher EGR rates - suspect a failed HFM if there are no air leaks in the intake tract.

The ISTA air mass/EGR test results or a TestO measurement could confirm and would be interesting to see.

[robnitro]

"While kat heating" makes me think of the egr cooler valve which chooses to cool or not cool the egr and is cycled as needed by the dde while driving to obtain egr flow needed

[spadilla7]

To everyone, thank you or the insight. Now I need to see what Rheingold actually is and how I get it. I am not up on the terminology.

Thanks again for the help.

[Miko226]

Delete and Remap!

[spadilla7]

Since I dont have Rheingold. I did do a couple of simple checks on two of the components connected to the egr cooler. I started the car to see if the car made sufficient vacuum. It did, nice and steady at around 29 mmHg.

The first check was on the electronic valve on top of the cooler. I disconnected both vac lines and power. I connected a 12v power source and heard the valve click. I then checked vac while the valve is closed and then open. It operated as I think it should, meaning it held vacuum while closed and lost vacuum while open(energized).

I tested the actuator under the egr cooler, and while applying vacuum, I could see the arm retract from left to right, either the door closed or opened on the EGR cooler, not sure which. I hooked everything back up and started the car. The vac actuator's arm was all the way to the right. One thing I cannot check right now is if the actuator arm moves back left under boost. I mean it should, right?

Without Rheingold or some other type of software, is there any other manual checks I can do to try and diagnose the problem?

As always, I appreciate any guidance.

[robnitro]

Not under boost but it will use the cooler to get denser egr flow. Under throttle/boost the egr valve by the intake actually closes.

I think it might always be in use once the engine is warmed up, iirc from reading a document a while ago. On the older vw tdi, the cooler was always in the loop, on bmw I think it doesn't use it when engine is cold because it affects emissions then.

The temp sensor might be bad but it's hard to check without software.

If you have a windows laptop and get a k+dcan cable, installing Rheingold is simple

[spadilla7]

Originally Posted by robnitro

Not under boost but it will use the cooler to get denser egr flow. Under throttle/boost the egr valve by the intake actually closes.

I think it might always be in use once the engine is warmed up, iirc from reading a document a while ago. On the older vw tdi, the cooler was always in the loop, on bmw I think it doesn't use it when engine is cold because it affects emissions then.

The temp sensor might be bad but it's hard to check without software.

If you have a windows laptop and get a k+dcan cable, installing Rheingold is simple

I replaced the temp sensor on the EGR cooler about a week ago or so. Is there a particular k+dcan cable that works the best, or does it matter which one? Never mind, I ordered the cable from Bimmergeeks and also used their link for software.

[spadilla7]

So, I finally got Rheingold 4.6 ISTA/D hooked up to the car. Pretty simple to use actually. The bimmergeeks cable works really well also.

What did I find? Well, the above mentioned code pointed to a bad EGR Cooler flap, door whatever you would like to call it. I ran the test and the actuator door did not perform properly. So, I cleared the adaptations and reran the test. It passed the second time. I also cleared the adaptations for the EGR since it was replaced as well. Not sure if that will solve the issue because......
It can be related to CBU.

So, I ran the Intake Sooting test. It failed miserably. As the test increased the RPMS in three steps, the predicted air flow vs measured was way off. The actual airflow was almost flat, meaning the car is literally suffocating. I figured the CBU service needed to be done, but to visually see it happen in real time was convincing enough.

Now I need to find a shop to do it. I can do it myself, I prefer to do it myself, but I just don't have the time.

Any recommended shops in the Tampa Area? I am all ears.

Thanks!