It can be done in the car, but it's a pretty big job. Cam covers, timing cover, front pulleys/belts, harmonic balancer would need to come off, maybe...
Is it the same code? If it is the same code, there are 3 electrical connectors that could be loose or corroded. The one at the sensor, the one where...
Well...my resurrection has died and needs another resurrection! Engine seized up last week while driving home. Ugh! Now the arduous process of trying...