Fun times fellas. Past 24 hours of my life have been dedicated to figuring out WTF is going on with my left e-brake. So here are some troubleshooting tips to speed run you through this and a story. Short answer: if you hear clicking coming from the motor or caliper. Replace the part that is clicking. I’d expect this to happen in a high mileage situation. If the motor keeps spinning it’s most likely a waren out coupling. Or if you replaced the motor or the caliper it may also be the wrong part. There are two types of coupling if I’m not mistaken a 7mm and a 8mm though it might be 6.5mm and 7.5mm I don’t know exactly. If you verified that you have the right parts, the motor runs off a 9V battery, and couples with the caliper correctly, the time has come to take it to the Diller or a certified Volvo mechanic. You did all you could. Here is the long answer for the folks that like to get up close and personal with the car. Control module is actually pretty good so if it throws a warning it’s most likely the real deal. You can check if your alternator is giving out the correct voltage, though if that’s the case you should be experiencing more than Parking brake problems, so i wouldn’t go down that road. If you can hear the motor spinning it is not a wiring or ECM issue and if your mechanic tells you to replace that but the motor is spinning RUN!!!! To another mechanic of course. Unless this is the 4th hour of your at home break job and you can’t set this thing to work in which case sorry for the digestion. I’ve been reading up on other people’s experiences and it’s wild. IMPORTANT: you should always secure the car if you are doing this at home. I am aware that older Volvos are interesting cars to fix for the motorists that like a challenge but garage repairs require extra precautions so get some jack stands and loosen the nuts before liftoff cause with that e-brake off it is spinsville. IT IS EXTREMELY IMPORTANT: that you jack a car for this type of a job in a correct way. Before jacking anything up you need to put the car in park, disengage the e-brake, get out, push the car until your parking gear clicks in and secure the wheels. If you don’t do this and jack up the car it may move as you are jacking it up or worse as you are working on it and potentially FALL ON YOU!!!!! I CAN NOT STRESS THIS ENOUGH, YOU NEED TO SECURE THE CAR CORRECTLY. As an extra procussion maybe work on one side at a time while securing the while on the other with bricks or similar. Anyway, let’s say you replaced the rotor and pads. And somehow you ****ed up (don’t take this close to hart it happen to me too many times). You might have forgotten to disengage the e-brake before disassembly for instance. Which if you read the paragraph above you absolutely should not do for safety reasons to begin with. This throughes off the position that the car thinks the e-brake is in and makes the ECM freak out. All you need to do. Is to pull the parking brake during the start, for the ECM to find the new open limit and you should be good from there. You might have to compress the piston and rewind it but as long as you can hear the motor start and stop and not run for 20-25 seconds (that’s when ECM times out the motor) you will persevere. I believe in you 💪 You need to clear the codes after. There are many code readers. Do your research on this. I’d recommend getting one that is programmed for your model. It’s a few hundred but is well worth it. But this is the best case. Now what if the motor keeps spinning 😐 and times out. This is where we really separate the man from the boys, fellas. You need to figure out why is it free spinning. Couple of ways to go about it. Here is the fastest. Disconnect the electrical plug from the motor and get the caliper off the rotor with the motor still attached. Get a pack of 9V batteries you might end up using up a few it is kinda fun spinning that thing. Energize the motor with the battery. What you are looking for is to see if the motor can actually expand the caliper when it spins one way and if it can reach the open limit when it spins the other. To change the spin direction flip the +/-. There are ways to do this with the e-brake button but the time it takes running back and forth from the driver’s seat to the rear brake, especially the rear right can get really frustrating. Scenario One: You did not change the caliper or the motor. If the motor keeps spinning It suggests a mechanical issue in either the caliper or the motor it could also be a waren out coupling which makes the motor free spin. Keep an ear out for clicking sounds and uneven spin speed. Scenario Two. You did change one or the other. Well you might have gotten the wrong caliper. There are multiple version of that rear caliper with different couplings: the more expensive and the cheaper one, also at least one that is out of production though it can couple with the expensive one. Why? I am not going to even attempt to fathom. All you really need to know is that if your car has the expensive setup and you install the cheaper caliper the motor will free spin. The other way around part will most likely not fit at all cause the coupling is not only slightly different in diameter but also in the number of teeth. Though I never counted to be honest. Of Course if the motor is not spinning it can be: the motor itself, which you can test with a 9V battery method described above. Faulty wiring harness: you can check that with a tester. I wouldn’t mess with the ECM. But if you are determined to try everything you can try replacing the battery and the alternator cause you could be experiencing low current issues. Now I personally draw the line at the wiring harness. If you verify that you have the right parts, the motor runs off a 9V battery, and couples with the caliper correctly, the time has come to take it to the Diller or a certified Volvo mechanic. You did all you could. I promised a story though so here you go. I drive a 2016 V60 2.0L i4 with about 150k miles on it. I’ve been getting the high pitched sound that I’m sure we are all familiar with from the brakes when reversing. Brought it to JiffyLube for an oil change and had them check it out. Side note: I always bring my own oil and filter and recommend for you to do that too. Mine takes 0W-20 high mileage with a 10k miles filter. The oil service interval on those in 10,000 miles or 12 months. So if you put less than a 10k mile filter or oil the oil change warning will come in too late 5,000 to 7,000 miles too late 😅. Which after a few times of doing will start screwing with your motor and more importantly the turbo. Anyway, we checked out the brakes and surprise surprise I need a new set all around. Which is fine, though the braking performance was ok, I was in the mood of getting a fresh set anyway and with how warped the front rotors were it couldn’t be helped. As they change things out we find a seized up caliper on the rear left. No big deal right. In for a penny in for a dollar, let’s replace the caliper. I leave it to the mechanic and come by at the end of the day to pick it up. The mechanic comes back from the test drive and informs me that the e-brake working hase come on and that it may be an electrical problem or a problem with the motor. I respectfully explained to him that that’s a load of bull**** and that he most likely did not reset the e-brake correctly. We spend another hour disassembling and reassembling the brakes resetting e-brake the hall shebang. And nothing the warning goes away momentarily but comes back if you try to engage and disengage the e-brake. Though the car drives fine it beeps and flashes warnings like a jet filter with a missile lock on it. Keep in mind it is 8:00 pm, an hour after closing and nothing but junior mechanics closing up shop. So I settle the bill, which if you wanna do it “Right” you should not do. But at this point I’m thinking I’ll just go home put the car on the stand and f*** around with it until the ECM recalibrates, I’ve changed the rear brakes before and know how to reset it, easy right. WRONG!!!! I get it up on the stand and try to reset it but same thing until I hear the motor spinning. Even if I turn the car off it keeps spinning until it times out in both directions !!!! I pull the caliper off hot wire the motor to a 9V battery and of course it does not push the cylinder as it should but also can’t wind the parking brake all the way to open position. I open it up, split up the caliper, measure the diameter and sure enough there is a whole millimeter of difference in diameter. Long story short after 4 hours of troubleshooting I had my answer. I tricked the ECM to think that the parking brake is disengaged to turn off the warning, and was able to go to bed knowing that there is nothing wrong with the car. Next morning I took it back to the mechanic and was able to look at the new and old caliper side by side to confirm the one millimeter difference in the couplings which BTW is really hard to spot with a naked eye unless you know to look for it. Of course the correct part costs $200 or so more, but at this point it is what it is. I’m currently sitting at the mechanics waiting for him to fetch the right part 🙃. Which is why I had time to write this essay. Hope you found the information you have been looking for. Stay safe out there and wear gloves. Good Luck