Odd Warning Messages

[artyman]

A week or so ago I had a warning message pop up on the dash saying that Cruise Control/ Limiter was inoperative. Cruise Control was working fine yesterday, then also yesterday a warning that the left rear light/brake light was inoperative. Both the lights are working!!

Any suggestions, and is a cure likely to be expensive?

 

[M5 London]

How old is your battery ?

 

[artyman]

How old is your battery ?

I wondered that, though it starts without any problems, Eleven years old I would imagine, I've had the car since it was two years old.

 

[johnsco]

Eleven years old is quite old for a battery.
It may still start the car - But as it does so, the battery voltage may drop momentarily to a point that causes "nuisance-triggering" of some alarm conditions.

 

[clk320x]

Eleven years old is quite old for a battery.
It may still start the car - But as it does so, the battery voltage may drop momentarily to a point that causes "nuisance-triggering" of some alarm conditions.

unlikely when the engine is running and hence alternator running.

 

[M5 London]

I wondered that, though it starts without any problems, Eleven years old I would imagine, I've had the car since it was two years old.

I would suggest, considering its 11 years old, that a pro active battery replacement would be in order, considering the relatively low cost, ease of change, winter coming up and its had a pretty decent innings to date.

Batteries fail over time, I believe that's a fact.

 

[zipdip]

I agree changing the battery is a wise move,it may well be a cheap fix for your problems.

 

[artyman]

Is swapping the battery a simple disconnect or is there a procedure to follow so it doesn't have an electronic brain fail.

 

[johnsco]

unlikely when the engine is running and hence alternator running.

The voltage drop occurs at the instant that the start-solenoid makes the connection.
This is the instant of maximum current drain from the battery and is before the alternator (or anything else) starts turning.
It is also the instant at which the greatest voltage drop will occur due to the internal resistance of the cells of the aging battery.

 

[markjay]

I agree that the battery is a likely culprit.

But have you tried reading the stored fault codes?

 

[grober]

Might be worth checking the rear SAM unit in the boot for water ingress

 

[artyman]

Might be worth checking the rear SAM unit in the boot for water ingress

[numpty]Where would I find that and what does it look like [/numpty]

 

[grober]

Its usually located behind one of the side trim panels in the boot Its got lots of fuses relays and a connection to the vehicle canbus. You really need Star to read any fault codes but at least you can inspect it for water damage from leaking seals/ seams. If you google W203 rear sam you will get lots of pictures.