C5 X7 faulty BHI?

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Monad
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C5 X7 faulty BHI?

Post by Monad »

Hello all,

I've recently taken on an '08 X7 Tourer that was going for reasonable money (or perhaps it's just a form of madness :lol:)
Engine and Gearbox are sound, but the hydraulic systems doesn't respond to cabin commands and the car is showing "Suspension Faulty".

I'd managed to get it home, gently, and I'm getting stuck into resolving the issue.
The diagbox session I ran when inspecting it revealed the following codes for the suspension ECU:

U1116 x2
U1117
U2005

I've come to understand from browsing a few threads on the topic that these codes aren't uncommon, I've had the front body position sensor out of the car and tested on a bench that it is powering up, and with diagbox monitoring the suspension ECU parameters - both filtered input from the front and rear sensors show "000" with no reaction when manipulating the front sensor.
(I'd pre-emptively ordered a new one on the off chance it was a simple as that, d'oh).

All fuses appear to be intact in the relevant locations, with the original 40A fuse in place for the Hydractive system.
I can hear the solenoids clicking when testing in Diagbox, and when I run the pump test it spins for a second or so and stops.

I've checked the connector for the suspension ECU and the pins appear to have some gunk in them, perhaps some gelled up LDS?

In short, I've convinced myself in the course of writing this post that I think I need to get a new BHI, is there anything else worth trying or checking before I pull that trigger?

Thanks!
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GiveMeABreak
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Re: C5 X7 faulty BHI?

Post by GiveMeABreak »

U1116: Suspension ECU data not valid fault: Protocol controller not functional. This basically means the CAN controller for this circuit is not working.
U1117 is only for V6 and 2.2 vehicles with suspension separate ECU - so shouldn't be relevant to a 1.6.
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Marc
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Re: C5 X7 faulty BHI?

Post by Monad »

Hi Marc,
Thanks for that - so what I'm getting is a load of nonsense from it, and a replacement is probably in order?
Not sure what you mean by "1.65" though, the VIN if useful is VF7**************[VIN obfuscated, can be read by forum staff].
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GiveMeABreak
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Re: C5 X7 faulty BHI?

Post by GiveMeABreak »

A typo - I meant 1.6 as in engine size, which only have the built-in suspension ECU within the BHI, and not the separate CDD suspension computer for V6 and some 2.2 models. An d of course I looked at your topmost vehicle list to note the 1.6 Tourer you have, but same applies for the 2.0.

Ok, so with the VIN this helped as this is a general communication fault code (U1117) and can appear on several systems that are interlinked. I checked the ABS / ESP and this is coming up there as a fault. Diagbox should have listed the system where the fault was detected in order to narrow it down, so I can only list the code under the ESP system. U2005 is a normal ghost fault that appears when the suspension ECU is interrogated by the diagnostic tool.
Fault Code: U1117
Description of Fault: Fault no communication with the intelligent hydraulic unit ECU: No signal. The time of appearance of the fault code is 2s. No transmission of datastreams by the intelligent hydraulic unit ECU.
Conditions for Fault to clear:
  • Transmission of datastreams by the intelligent hydraulic unit ECU
Downgrade Modes whilst Fault is active:
  • No back-up mode
Symptoms: -
Suspect Areas:
  • CONNECTORS
  • Line CAN
  • ESP ECU
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Marc
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Re: C5 X7 faulty BHI?

Post by Monad »

Aha I see. Thank you for the further detail, I'll dig in some more before I call our local specialist.
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Re: C5 X7 faulty BHI?

Post by Monad »

Had another look today, and sure enough the global test shows U1217 under the ESP ECU as well.
I've removed the BHI and will try to source a replacement for a next step.
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Re: C5 X7 faulty BHI?

Post by Monad »

It took a while for it to occur to me - the pump is operational, and the electronics respond during testing.
Exactly as Marc had said, U1117 doesn't make sense to occur on my car - I've re-installed the BHI, checked it's coding and it was set for the incorrect engine type.

After refilling the car with fluid and bleeding, the back end rose up immediately, but the front is still yet to rise much.
A brief pogo-ing drive up and down the road and sure enough the front body sensor is now reporting as faulty.
Good job that replacement is on the way :D
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Re: C5 X7 faulty BHI?

Post by GiveMeABreak »

Great, well done and thanks for taking the time to update the thread.
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Marc
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Re: C5 X7 faulty BHI?

Post by Monad »

Just following up to close this thread off,

After the BHI being reprogrammed, the ride was terrible as well as the normal ride height being off.
I've just swapped both front spheres and it's now driving wonderfully - and the new ride height sensor has just landed in the post.
A bit more tinkering and I think we're there.

I wouldn't have been able to get this far without the knowledge documented throughout the forum - so thank you all.