2001 Volvo S80 reads check brake light, manual cal...

bad ABS module

Check & replace if necessary the Brake Pedal Position (BPP) switch placed above pedals on the support.

position bulbs are tail lights and marker lights.emmisions service is the same as check engine light. take it back to the shop. something left unpugged jarred loose etc.

1156 and 7506 are not the same. the euro cars when you replace the bulb, need to be the right number or it causes this issue. the different casings causes resistance. 1156 s are common bulbs they shouldnt have done told you that but thats why they are parts guys and im not.

relay ?

Bulb position light failure indicates that you have a burned bulb somewhere around the car. Check all of them. Brake lights, parking lights, flasher and so and so.

This is a very common problem with Volvo.

You could alo get this problem eventhough no bulb is burned. If it's the case, test each bulb contact in their socket playing with them. Make sure you put some electric grease on contact replacing the bulbs.

Check if there were a recall for your specific vehicule and if it has been done on yours. I know that during the years, some recalls were adressing this type of problem.

Regarding whistling noise during warm up try to remove oil filling cap during engine is running. if the noise stops it's probably the PCV that is blocked and need to be replaced. If it doesn't fix it, let us know and we will go more in depth.
Hope it helped
Dan

This would be a bulb problem. You can open up your trunk, pull back the liner, and find the screws that hold the lens on, remove the screws, pry off lens and then push in and turn counter clockwise to remove the bulb. Then the new bulb pushes in and turns clockwise to lock in place.

most likely your brake light. Also if no brake lights are out, volvo is notorious for putting the wrong bulbs in from the factory. If they work take them out, if they have an orange bottom inside the buld replace the bulbs. I used to be a volvo tech. I would replace both so you dont run into this problem again

Could be the break light switch whitch is usually found on the break pedal lever (just above the break pedal)..
If that is it - should be not to hard to replace..

did u change both bulbs anyway