There's an old paper TSB on replacing both individual sensors with one pair wired togther with its own new wiring harness ("new and improved") but that was Volvos original idea way back in '94. They originally thought that the problem was bad connections at the knock sensors. I've done it to a few cars and in each case, the cars all came back with the exact same codes. The new knock sensors with improved connections didn't solve the problem. In each case, a replacement ECU (new or preferably used now) solved the problem. I now don't even try replacing the original '94 type knock sensors anymore as I know it'll just come back.
I've never seen where bad cap, rotor, wires caused that code to appear.