گرفتگی یا پارگی شیلنگ حس فشار

The thin hoses that carry exhaust pressure to a sensor mounted safely away from the heat — the particulate filter's differential pair being the classic case. They are the measurement's weakest link: soot slowly plugs them, heat splits them, and after any exhaust or filter work the pair can be refitted swapped, which reverses the reading's sign while everything measures electrically perfect.

A blocked hose produces a believable wrong number, not a dead signal — which is why this cause outranks the sensor on most of the codes that list both, and why it is the specified first check whenever a pressure reading stops tracking the engine. The repair is minutes and pennies; the misdiagnosis it prevents is a sensor at best and a condemned particulate filter at worst. After exhaust work, "were the hoses swapped?" is the first question, not the last.