Mercedes-Benz C-Class and C-Class AMG: How to Reset ECU and TCU

This article covers how to reset the ECU and TCU on your C-Class or C-Class AMG, quickly and easily.

By Brett Foote - May 19, 2015

This article applies to the Mercedes-Benz C-Class and C-Class AMG (2007-2014).

Modern cars like the Mercedes-Benz C-Class "learn" your particular driving style over time and miles driven. For those who have acquired a used car and want it tailored to their own driving style, or those who just simply want to start over, resetting the ECU (engine control unit) is a good way to go. The ECU reads values from a series of sensors to adjust engine actuators for optimal engine performance. The same can be said for the TCU (transmission control unit). The TCU uses sensors and data collected from the ECU to determine when to shift gears for optimum performance, fuel economy, and shift quality. Resetting both is a very easy and quick task that anyone can do. Keep reading to learn how it's done.

Materials Needed

  • None

Resetting the ECU

Step 1 – Disconnect the negative battery terminal

Simply raise the hood and disconnect the negative battery terminal.

Step 2 – Reconnect the terminal

Wait ten minutes, and then reconnect the terminal. Your ECU will be reset.

Figure 1. The negative battery terminal is on the left (black).

Resetting the TCU

Step 1 – Turn key to 'on' position

First turn the ignition key to the "on" position just before you crank the engine to start. Press the gas pedal to the floor and hold for 5 seconds.

Step 2 – Turn key to 'off' position

Turn the key to the off position but do not remove the key, then release the gas pedal. Wait at least two minutes. The TCU is now reset.

Figure 2. Simple manipulation of the gas pedal and ignition key are all that is needed to reset the TCU.

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