What to Do When Your Mercedes Starts Then Dies After Engine Mount Replacement

A reader reached out with a frustrating problem: their Mercedes starts up fine but immediately shuts down. The car had been running without issues until they replaced the passenger side engine mount and the transmission mount. Now they’re wondering what went wrong, and where the infamous P0110 sensor is located.

First, let’s talk about the P0110 code. That’s a trouble code pointing to the intake air temperature (IAT) sensor circuit. This sensor is typically mounted in the air intake duct or on the intake manifold. During engine mount work, it’s easy to accidentally unplug, damage, or knock loose a wiring harness near the intake.

A disconnected or shorted IAT sensor can cause the engine computer to get confused and kill the engine immediately after startup as a safety measure.

The fact that the car started fine before the mount swap strongly suggests something got disturbed. Check the wiring around the intake and the sensor connector itself. Also verify that you didn’t pinch or break any vacuum lines or ground straps while wrestling with the mounts. A loose ground can also cause a no-start or immediate stall.

If everything looks connected, try clearing the code and see if it returns. If it does, the sensor may need replacement.

For professional diagnosis, bring your Mercedes to Boca Auto Care. Our technicians know exactly where that sensor lives and how to get your car running smoothly again. We see this kind of issue more often than you’d think, mount jobs can be tricky, and one overlooked connector can bring a whole car to a halt.