Bench Techniques
Reading the AOP: What "probe=0" and "no pulse" Actually Tell You
By Alex Rodriguez, repair technician · September 14, 2026 · 7 min read · Leer en español
Those cryptic SMC lines aren't noise. They're the always-on processor telling you, in its own terse language, exactly which sensor stopped answering.
Buried in most SMC panics you'll find lines from the AOP — the always-on processor that babysits the sensors. They look like alphabet soup: handler names, hex, "probe=0", "!pulse". Most techs scroll past them. Don't.
"probe=0" means the AOP asked a sensor "are you there?" and got silence. "no pulse" / "!pulse" means the expected heartbeat from a sensor never arrived. Eiger is the sensor hub driver. Put together — "Eiger::probe=0" — the hub polled a sensor and it didn't answer.
The trick is that the handler name tells you which sensor family: proximity, ambient light, barometer. Cross that with the missing-sensor line (when there is one) and you have two independent witnesses pointing at the same flex.
Our analyzer now attaches these AOP lines as supporting evidence automatically. But even reading manually, the rule is simple: probe and pulse lines are the AOP's way of naming the unresponsive sensor. Learn to spot them and SMC panics stop being intimidating.
From the log
AppleAOP: ... Eiger::probe=0 [e4 30 1]
Filed under: SMC · AOP · Eiger · diagnosis
Check your own log
Have a panic-full .ips file from a phone doing the same thing? Run it through the free analyzer — it reads the file locally in your browser and shows you the evidence it finds, the inspection targets it ranks, and the next checks it recommends.
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