Hi I have a 2005 volvo s40 t5 my due for service light came on I did the service but can I reset the computer in car or do I take it to volvo dealer to reset it

Internet search suggests faulty alternator, after testing and cleaning battery cables, but some after market alternators also continued to display the error, so be careful in purchasing a replacement alternator.

https://volvoforums.com/forum/volvo-s40-11/2005-s40-t5-power-system-urgent-service-64180/

https://forums.swedespeed.com/showthread.php?336857-quot-Power-System-Service-Urgent-quot-Red-Dash-Light

Possible water pump failure. Was temp guage showing "hot" ? , if not maybe coolant sensor issue. Had the car just been driven hard ? Any pressure in coolant expansion tank ?

My S40 T5 makes a whirring sound due to the turbo but.... I did have an issue with the right front hub bearing. Lots of road noise while driving and it got louder as I accelerated. $215 dollars for the part.

Car not starting or turning over indicates towards multiple possibilities. It can be issue with battery or weak battery. But if battery checks out ok, then it can be starter issue or faulty alternator or problem with low fuel pressure or no spark at spark plugs due to dirty spark plugs or faulty ignition coil or injectors getting cracked or dirty and needs to be cleaned.

To confirm the problem, the basic troubleshooting is required.

Click this link below and follow the troubleshooting:------

http://technoanswers.blogspot.in/2012/02/car-starting-issues.html

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This will help.

Thanks.

depends whats wrong to start with and what needs changing ,a compressor cost around 600euros alone

if computers arent picking anything up its not an electrical fault, sounds like your surging because of bad fuel or blocked injectors, run some fuel cleaner through the car and see if that makes a difference. fuel filters may need to be changed but try the cleaner first.

unhook possitive post on battery....wait and then reconnect...this usually works...make sure fuel cap is always tight and never leave car running while refueling. this causes 85% of engine lights coming on

turn the key on to position 1 preset miliage trip button anh hold for 2 second release and turn key to position 2 hold within 4 secods and hold til manitance info clears.

A lot of new cars have this as a reminder for the owner to change the oil and when this is done the mechanic should reset the light to go out ,look in the owners manuel there should be something in it to tell you about this light other issues that will arise.