Specialist can't reset fault warnings

[GiveMeABreak]

It's too big a subject to cover here, but on a multiplexed network (let's use the X7 here), the RCD line (remote controlled wake up) has the following ECUs connected to it, allowing an early wake up of these systems:

• Built-in Systems Interface
• Engine ECU
• Suspension ECU
• Variable Damping Suspension ECU (on V6 X7 models only)
• Deflation Detection ECU (Tyre Pressure Monitoring System)
• Automatic Gearbox
• Electric Parking Brake

These systems are partially or fully awakened from an RCD event - which can be the opening of the car locks by the fob or the key for example or opening a door.

So ignition + using the key is no longer relevant for these systems - they can all be brought to standby or awakened from an RCD triggering event.

In such cases where we want the BSI and all the ECUs to go back to sleep, we need to keep the doors closed (or manually lock the latch), which tells the driver's door control module that the door is closed and in turn this master ECU informs the BSI the door is closed. So after some, leaving the car in this state will allow the networks to back to sleep - until a door is opened (which triggers the BSI to start partial wake up again).

[wheeler]

So if you can't leave the window open, flip the door lock manually so the BSI thinks the door is shut.

That's a way round it!

So, when Wheeler says that it's not really necessary to make sure that the door is closed, just leave it alone for a while that this doesn't work at all? Or maybe only for earlier cars?

The BSI will indeed shut down with a door open, this was certainly the case on earlier VAN/CAN models. As long as the door status does not change it will go to sleep. I wasn't as sure about later full CAN versions so I have just tried it on my X7 with the drivers door & bonnet open, The BSI does shut down, it takes around 5 - 6 minutes, if you then close the door the BSI wakes back up.

[xantia_v6]

The BSI will indeed shut down with a door open, this was certainly the case on earlier VAN/CAN models. As long as the door status does not change it will go to sleep. I wasn't as sure about later full CAN versions so I have just tried it on my X7 with the drivers door & bonnet open, The BSI does shut down, it takes around 5 - 6 minutes, if you then close the door the BSI wakes back up.

How do you tell that the BSI has shut down?

[GiveMeABreak]

Yes, ^ the BSI may not show any obvious signs; there are 5 life situations and 9 life stages that it can cycle through depending on various timings and inputs. When you are specifically trying to troubleshoot an ECU or one of the networks, I personally would suggest ensuring the BSI is asleep and that all the ECUs have written their data. The best way to do that is to manually latch the door catch if you have to have the door open, which simulates the door being closed - and is actually officially referred to in one of the many procedures I was reading a few weeks ago.

On that matter generally, I'm deciding whether to put something up on multiplexing in the Diagnostics section, or whether it's a bit 'out there'...

[wheeler]

How do you tell that the BSI has shut down?

You can tell by measuring the current draw from the battery at rest, you can see the current flow drop in stages as the BSI is shutting down in different stages . It should finally settle at around 0.04 - 0.06 amps you know the BSI is shut down when it reaches that figure.

[Leigh123]

I have a 2007/8 C5
Have been away for 3 weeks car started with a slight hesitation but ran good once started.The problem I have is not the acc blower in not working at all ,never had any problems until I restarted the car.I have had it checked for power going to the motor that's all fine.Was wondering if a BSI restart might sort the problem or any other ideas.

[GiveMeABreak]

I think you'll find that there is moisture that builds up in the motor and where it is left sitting, the damp can cause a little rust and can seize the bearings. The motors are generally designed to start off slowly and then build up power. In your case it's probable that there is not enough welly to start the motor off. Others here have jumped the connection in the plug so that it applies full power at the start to get it going.

[Paul-R]

Start here and follow my link.

viewtopic.php?t=61237

And this one: viewtopic.php?t=62347

[admiral51]

Late to the party on this one but i cannot see any faulty codes listed ?
I work in Southampton Monday to Friday and have a Lexia and am more than happy to have a bash and see what fault codes show up.
My problem is i am now away on holiday until 29th so the offer is there but cannot do anything for a week or so unless circumstances change.