Every time a stem-mounted TPMS sensor is removed from a rim or is disturbed, it must be serviced — no ifs, ands or buts. This goes for sensors that are six months old to six years old. Do not reuse seals or stems. You are not doing the customer a favor by reusing old parts.
Don’t Torque Twice
A leak will not be eliminated by further tightening the nut. The sealing grommets are engineered to work at a specific torque. Any torque above the specified value will cause the seal to leak, and extra force may damage the nut and stem or fracture the sensor body.
Every 10° F of ambient temperature will change tire pressures about 2%, or about 1 psi. So, as the seasons change, and as 70º F dips to 20º F, that could mean a difference of 5 psi and a TPMS warning light. Adjust the pressure for the temperature outside and not the temperature in the bays.
Just be aware that if there is interference, especially inside, moving the vehicle outside (or even sometimes another foot or two if the caliper is causing the interference) is usually enough to clear things up. Don’t let someone who’s reheating their lunch spoil your relearn procedure.
It is completely normal for air to escape the tire and rim naturally and cause as much as a 1.5 psi drop per month. This is why monthly manual service checks are essential for keeping a tire healthy.