The car starts and runs fine, but the engine warning light is on all the time, plus there is a display that reads Motor System- Service required, what might be the problem? Its a 2002 Volvo S60

Hook it up to a scanner that reads both OBD2 and ABS and read the codes. I had problems with GM vehicles and it was usually the ABS or another harness that was actually the problem.

i'd say you need to get the engine diagnostics read and cleared to start engine , and get a service a suggested

NEED CODE FAULTS AND THE ECUS THAT THEY COME ON!!

check for alternator and starter motor functioning ok , does it turn over and not fire up or not turn over at all?

Yes it may be the wires are shorting or its actually the problem with instrument cluster.
Also get the vehicle scanned for any error codes stored in computer this will confirm whether is short circuit issue or actual problem:------
I suggest you few help links with accurate solutions to refer/go through:----Click the link below:------

Battery and brake Warning lights on Dash
http://alltypesofpartsreplacing.blogspot.com/2012/10/battery-and-brake-warning-lights-on-dash.html
--------------2002 Ford Windstar: Brake Warning Light ON dash? http://schematicsdiagram.blogspot.in/2012/06/2002-ford-windstar-brake-warning-light.html
-------------ABS & Brake warning lights remains steady on dash? http://schematicsdiagram.blogspot.com/2011/12/abs-brake-warning-lights-remains-steady.html
-----------Chevrolet Tahoe Hood open warning on dash and alarm sounds? http://schematicsdiagram.blogspot.com/2011/12/chevrolet-tahoe-hood-open-warning-on.html
-----------2005 Chevy Impala: Service Vehicle Soon Warning Light? http://whoisbyme.blogspot.in/2012/06/2005-chevy-impala-service-vehicle-soon.html -------------- Malfunction Indicator Light ON http://whoisbyme.blogspot.in/2012/06/malfunction-indicator-light-on.html
-----------Car Runs Fine But Check Engine light is ON?

http://whatisbyme.blogspot.in/2012/05/car-runs-fine-but-check-engine-light-is.html

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Check engine light with codes P2195 and P2197?

http://howtobyme.blogspot.in/2012/01/check-engine-light-with-codes-p2195-and.html

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How to Read Codes from Check Engine Light? http://schematicsdiagram.blogspot.com/2011/12/how-to-read-codes-from-check-engine.html
-------------These will help.Thanks.

The light that looks like a car with an exclamation mark in the middle of it is the HYBRID WARNING light (see diagram below) You must scn the onboard computer network to determine why this light is coming on. You also need to scan your computer system to find out why the engine keeps dying. If the hybrid batteries are discharged, they must be properly recharged to prevent serious damage.

CAUTION: Read ALL service and warning lables in the engine compartment before attempting ANY type of service on a hybrid vehicle. The wiring harnesses that have ORANGE connectors are HIGH VOLTAGE connectors and can cause serious injury or death.

DO NOT touch any wiring harness or component that has a HIGH VOLTAGE warning label on it.

My recommendation is to tow the vehicle to a qualified hybrid repair center (preferably the dealer) and get it properly diagnosed and repaired. The high-tech, high voltage systems in this vehicle is nothing for anyone but a trained, certified technician to be messing with.

A diagnostic scanner that reads OBD1 (the system by which your vehicle processes trouble codes) will be required, many parts stores do this a s a free service. Check with them to see if they charge. Remember though, when they read the car and turn the light off that in order for the light to stay off, the problem must be fixed. Even if it was a one time fluke of a problem, get the code that their scanner gives them so that you know what the issue is.

the light needs to be reset (free at an autoparts store) also; have them check your battery and, your alternator

WHAT HAPPENED IS WHEN YOU SHUT DOWN AND RESTARTED YOU (RESET THE ENGINE MANAGEMENT COMPUTER) AND THE SERVICE LIGHT SHOULD GO OUT AFTER 10 MINUTES OF DRIVING