A bunch of messages and will not start.
 

Hi I have a 2007 P3 S80 D5. I've had the car about 3 months. Its had little use probably 2k sine I purchased..
Soon after buying the car I had the 'Alarm requires Service' message displayed. I understand the Alarm Battery problem so left alone. 1 week ago I had the 'Parking Aid requires service' message displayed. 2 days ago we took the car out after standing for a week. No problems other than 1 of the above messages. We drove approx 10 miles then parked up. We sat in the car for 5 minutes then 'Steering lock requires service' message came up. We returned to the car and it started without errors. Car was left standing for 2 days. Went to start this morning in -2 deg. Errors coming up and fails to turn over. To add insult, when I try to eject key another message appears 'Engage P before removing key'. It is in 'P'. I can hear a clicking in gear selector area. Some how I managed to get the key to eject after shifting into drive, then 'P' then taking foot off brake pedal. My thoughts are the battery although I'm not convinced. Its not often used and never failed to start on the button. Thoughts Please.

charge your battery if the warnings dissapear think about buying a new battery cold weather and lack of use can soon kill a weak battery .

I wiggled the steering wheel and it started. Left running for 10 mins, switched off and........ It wont start, and ....... New message ' Hand brake requires service' What the?

Battery can cause all sorts of issues.

As mentioned above, charge it & go from there. It needs a good charge overnight to give it a good boost. Don’t use any rapid modes or boost modes on your battery charger because you’ll kill the cells. Just charge on “normal” mode… a trickle charge is key. Rapid charging destroys batteries.

I'd also suggest doing the battery before anything else - I got my replacement Bosch from Tayna - https://www.tayna.co.uk/car-batteries/types/096/
I needed a 096 AGM because I have start stop, I think yours is pre-start stop. Double check your battery number but I'd suspect it's a 096 like mine.

If it continues to lose charge with a new battery you might find the alarm siren batteries are causing that.

Yesterday the temperature outside was around 0 Degrees. Today around 5 Degrees. The car started without any errors or problems. New battery ordered.

My friend had bad battery. He had 13 errors on diagnostic tool.
after he change it, nothing apearred anymore

If the car isn’t being used much, it may be worth charging the battery every so often. Even a new battery will lose charge over time if the car is just parked up (not as quick as an old battery though).

New battery fitted. Getting random messages as previously mentioned. The car starts and drives some of the time. I'm assuming these faults are not in fact independent module faults but either bad signals or ECU error. I presume the ECU processes all this information. Can someone confirm if the ECU does in fact process this information, where it can be located, and if they can be repaired? Thanks

clear code and monitor which return check battery connections are tight also check earth connections