Mercedes Benz

P1384 Knock sensor 1 P1385 Knock sensor 2 The error codes P1384 and P1385  indicate a problem with the knock sensors, specifically Knock Sensor 1 and Knock Sensor 2 . A knock sensor's job is to detect engine "knocking" or "pinging," which is caused by abnormal combustion. When it detects this, it sends a signal to the engine control module (ECM), which then adjusts the ignition timing to prevent potential engine damage.   Common causes Defective knock sensors:  The internal components of the sensors can fail over time, leading to inaccurate signals or no signal at all. Wiring issues:  Damaged, corroded, or loose wiring in the knock sensor's circuit can cause intermittent or constant errors. This is a common failure point, especially if the wiring harness is exposed to engine heat or environmental factors. Improper installation:  Over- or under-torquing the knock sensor during installation can cause it to function improperly. The sensors are sensitive and req...