Limp Mode While Towing

MillerMav · #1 04-18-2021, 05:05 PM

Hey everyone, hoping to get some help. I have a 2013 X5, full deletes, Malone tune and Rod Sutphin trans tune. Normal driving conditions it runs great in all situations. I installed all the tow equipment last summer and had Bradley Tourt do all the coding. All is well there. I have pulled a few smaller items with no issue in the past. I recently bought a new camper and the current weight is around 6000lbs. I have a weight distribution hitch on because the tongue weight of 510 is a little light and I wanted to have a bit more sway control as well.

Anyway on to the problem.....as I said, without towing the camper the X5 runs great, pulls hard, no issues at all. When towing the camper no matter if I accelerate quickly or slowly the vehicle goes into limp mode at 65mph exactly. I tested it 3 times this afternoon. First time normal acceleration - failed, 2nd soft acceleration - failed, 3rd hard acceleration - failed. Everytime at 65mph. I pulled codes with my fox well scanner NT510 and this is what I have:

A1 03/Not Present - CAS immobilizer bus fault
2E3D/present - DDE interface EWS-DDE
2E41/not present - DDE interface EWS-DDE
428B/present - DDE boost pressure control low-pressure stage, control deviation
CF37/present - Message from car access system to body bus faulty. receiver EGS, transmitter car access system

Could it be that the camper is simply too heavy? Any help would be appreciated. I have about 6 weeks to either figure out the issue or get a different tow vehicle before our first tripped is planned for memorial weekend. Thanks everyone.

ard · #2 04-19-2021, 12:32 AM

Thats odd. Have heard of others pullng heavier loads, never heard of this issue.

Does it do it at 65mph, no matter the rpm? (ie is it a speed thing or rpm thing)

Malone, Sutphin and Tourt have any bright ideas??

MillerMav · #3 04-19-2021, 09:34 AM

RPM doesn't matter, its 65mph regardless of how I'm loading the engine. The FB diesel page seems to think its a vacuum issue. So I'm replacing the boost converter/controller piece and doing a thorough vacuum line inspection afterward. Basically, the thought is that under that heavy load the boost converter is weak and getting overloaded so the ECM is seeing a pressure issue and activating the limp mode.

smassey321 · #4 04-22-2021, 01:58 PM

Check for boost leaks. For the diesel check the red hose and also the intake hose. Both have failed on mine.

MillerMav · #5 04-26-2021, 10:08 AM

Quote:

Originally Posted by smassey321

Check for boost leaks. For the diesel check the red hose and also the intake hose. Both have failed on mine.

Thank you for the feedback. I replaced all the vacuum lines and front 1 (of the 2) controllers as well. While I was doing that I crawled under the car to give it a once over and noticed a lot of oil around the red hose. So I ordered that from Whitbread and also noticed two of the seals around the lower intake bolts was missing. I have a second controller and new set of "backup seals" coming from ECS by weeks end. I'm going to replace all the intake seals, the second vacuum controller and the intercooler intake hose this coming weekend.

I wasn't able to hook up the camper and tow yesterday because I ran out of time but on a quick run around the block (I live in the country so its a big block with no traffic) and without towing I had the car go into limp mode when I was approaching 100mph so I'm thinking there is some sort of correlation between heavy load towing and high speeds. It could have been that way for years because I don't think I have ever gone that fast that quickly in this car but I wanted to push it and make sure nothing exploded. Hahaha!

Hopefully after this weekend I'll have some time to hook up the camper and see what happens.

MillerMav · #6 05-09-2021, 08:25 PM

Replaced second boost converter and double checked all the vacuum lines. I also checked that the waste gate was functioning correctly. Unluckily any replacement intercooler inlet hoses are on back order so IDK when I'll be able to replace that. I also replaced all seals/gaskets on the intake manifold this morning.

Still going into limp at 95mph under WOT.

Pulled codes and got 428b which is the boost pressure control, low-pressure stage, control deviation. Researching that seems to lead me toward vacuum (don't think there is an issue there) waste gate function (seems to work) and tune. I have Malone tune and I found issues from 2018-ish but nothing much after that. I had Whitbread install the tune December 2019. IDK if that was still a problem then or not.

andrewwynn · #7 05-10-2021, 08:03 AM

Do this test; get close to the point it will limp mode and coast for a while then WOT and see if you can go a little faster.

If so, look into the vacuum accumulator hardware. Several instances of this being the culprit on diesels. Usually a big enough failure that it happens without towing and just going up hill steep enough. Possibly you have a small leak that only causes a problem at high enough engine load

MillerMav · #8 05-10-2021, 12:22 PM

Quote:

Originally Posted by andrewwynn

Do this test; get close to the point it will limp mode and coast for a while then WOT and see if you can go a little faster.

If so, look into the vacuum accumulator hardware. Several instances of this being the culprit on diesels. Usually a big enough failure that it happens without towing and just going up hill steep enough. Possibly you have a small leak that only causes a problem at high enough engine load

This worked! I went out a little earlier and got to just about 95, let off the throttle for a second then floored it again and got up to 115 before I just cut it off for fear of doing something stupid. Put it was pulling strong, no limp mode!

So, vacuum accumulator is that the vacuum reservoir? The black canister in front of the two boost controllers?

andrewwynn · #9 05-11-2021, 05:29 PM

Or any parts attached. Basically my understanding is the accumulator has vacuum reserve to run the turbo when heavy throttle eliminating vacuum source.

Some cars have a vacuum pump to increase vacuum when using enough throttle to reduce vacuum. I don't know if X5 is one of those

A vaccum leak anywhere can cause your symptoms. Find the leak. Let us know what you find

MillerMav · #10 05-12-2021, 07:42 PM

Turns out it was a pretty decent boost leak from two things.

1 - When I deleted the EGR, the plate that goes on the hole near the turbo was on backwards so it was allowing boost gasses to pass by slightly under normal use and a lot when under a lot of pressure. Took it off, flipped it around, solved

2 - The caps used for the swirl flap delete had shoddy seals. We replaced them with new caps that had better o-rings.....solved.

All is well now. Brad Tourt did a majority of the work and I am very appreciative he lives somewhat near by. He had a great DIY tool that connected to the inlet of the small turbo that he hooked to the compressor and would pressurize the engine to 40lbs. Made these boost leaks VERY obvious. I'm going to making one in the future because damn was it helpful.