Electronics

[RedXC]

I've been thinking, the newer Volvo models 01- have a CEM Central Electronics Module. Well, I've heard that by disconnecting the battery, you'll loose all or most memory to the car. As what one of the master tech at the shop replaced a CEM, now the car wouldn't start or function properly which we have to tow to the dealership because they have a more high tech and expensive VADIS/VIDA machine to program. I just don't just don't know why Volvo have to use everything to be computerized, i.e. window switch have to be programed after remove and replace. Independent Volvo specialist shop will have to spent hundreds to just get software for this minor or major components in the car.

[TrueBlue]

It's pretty well the same with most manufacturers - not confined to Volvo.

As demand from consumers for more and more gizmos grow (or perceived demand by marketing departments), coupled with demands from different markets' regulatory bodies become more complex; the only way that manufacturers can produce a vehicle for the money you are prepared to pay is by increasing use of computer technology.

There is so much going on under the covers to satisfy both the above sets of requirements that is not obvious to the consumer, that it leads to your comments. It's irritating, but on balance I'd not want to go back to a simpler regime - even if I could.

I think that on balance current cars are more reliable and more pleasant to use than their mechanically controlled forbears were.

I could write a book on the whole issue and load it with example, but I'd bore every one to death. I guess i've painted the overall picture.

Come back, anyone?

[JsR]

I enquired about whether I needed to take the cables off the battery before charging and was told yes. I was concerned about the computer memory, radio, etc., but was told "no, it'll all reset itself". I did as I was told and all was OK. Mine's a T6, '03, XC90 - hope this helps, but I'd say still check with the dealership before disconnecting...

John R

[Willy]

The complexity has to do with the CAN bus philosophy. The car is really a
computer network, all devices are members in the network. The CAN bus
is specifically designed (by Blaupunkt I think) to work in environments
with lots of signal noise, such as a car.
For example, if you switch on the headlights, the position of the switch is seen
by the computer who instructs the headlight assemblies to do whatever is programmed.
This may seem overly complex at first, but is saved a lot of wiring in a
car, and this is one of the main reasons of existance of the "networked car".
I think that in a car such as the XC, the length (and weight) of saved cable
is considerable.
Of course, the laws of nature cannot be defied, in this case (amongst
others) the law of conservation of misery (aka no roses without thorns) :D
Willy

[barrysharp]

The complexity has to do with the CAN bus philosophy. The car is really a
computer network, all devices are members in the network. The CAN bus
is specifically designed (by Blaupunkt I think) to work in environments
with lots of signal noise, such as a car.
For example, if you switch on the headlights, the position of the switch is seen
by the computer who instructs the headlight assemblies to do whatever is programmed.
This may seem overly complex at first, but is saved a lot of wiring in a
car, and this is one of the main reasons of existance of the "networked car".
I think that in a car such as the XC, the length (and weight) of saved cable
is considerable.
Of course, the laws of nature cannot be defied, in this case (amongst
others) the law of conservation of misery (aka no roses without thorns) :D
Willy

Willy & TrueBlue: very well articulated. :D ...also I agree with you both. :)