tp3r — Missing sensor
Watchdog panic: thermalmonitord no longer receives the reading from TP3R, an undocumented temperature probe, most likely on the logic board (same “TPxx” naming family as TP1A); with no response for ~3 minutes, iOS restarts the iPhone. Rare case: no confirmed repair found.
On iPhone XS Max, iPhone SE (1st generation)
Logic board (temperature probe on the board) — micro-soldering repair
Watchdog panic: thermalmonitord no longer receives the reading from TP3R, an undocumented temperature probe, most likely on the logic board (same “TPxx” naming family as TP1A); with no response for ~3 minutes, iOS restarts the iPhone. Rare case: no confirmed repair found.
First check
First test with a known-good battery, charging flex and power flex to rule out the parts; then board-level diagnosis by micro-soldering (thermistor line, short to ground, and according to a relayed report, the Tigris charging circuit).
On iPhone 12 Pro Max, iPhone 12 Pro, iPhone 12 mini, iPhone 12
Logic board (TP3R temperature probe, exact part not identified) — after ruling out battery / charging port
Watchdog panic: thermalmonitord no longer receives the TP3R reading and stops checking in; with no response for about 3 minutes, iOS restarts the iPhone. TP3R is a temperature sensor key from the “TPxx” family (like TP1A), which no primary source links to a named part. No public case on iPhone 12: the only TP3R cases found are on the XS Max (iFixit 973991) and the 1st-generation iPhone SE (iFixit 749276), both without a confirmed repair.
First check
First rule out the known parts: known-good genuine battery and Lightning charging port assembly (on an iPhone 12 mini, missing sensors TG0B/TG0V were attributed to the Lightning connector, iFixit 743040).
iPhone 12 Pro Max ›iPhone 12 Pro ›iPhone 12 mini ›iPhone 12 ›