Cruise Control allows you to take the foot off the gas pedal while still controlling the steering wheel. Your Mercedes-Benz takes over the acceleration and can maintain the speed without you pressing the gas pedal.
What does Cruise Control Inoperative mean on a Mercedes-Benz?
Cruise control imperative on a Mercedes-Benz means that you can no longer trigger the cruise control because of a malfunction (see common problems below).
There are three main reasons why cruise control may not work. The first is that the brake pedal switch is defective. Other possible issues include a dead battery or a faulty ABS wheel speed sensor. When an ABS sensor fails, you will also get ESP and ABS warning light to come on.
Cruise control inoperative is a common problem on Mercedes-Benz C300 W204, but this problem can affect any 2000 and newer Mercedes-Benz including E-Class, S-Class, ML-Class, GL-Class, GLS-Class, R-Class, GLE-Class, etc.
Cruise controls only work at speeds above 25 mph.
Cruise control inoperative
ESP light may come on
ABS light may come on
A yellow triangle may stay on
ESP, ABS, and Cruise Control Inoperative
Cruise control and Speedtronic inoperative
How to Reset Cruise Control Inoperative?
- Pull over and park in a safe location.
- Turn the ignition completely off.
- Wait one minute.
- Restart the vehicle, and the cruise control message should reset.
In most cases, this simple procedure will allow cruise control to start working again.
If cruise control inoperative comes up again, further troubleshooting is required. Let's take a look at common problems that cause Mercedes-Benz cruise control to stop working.
Why is Cruise Control Not Working?
Because a component or sensor required for the cruise control system to function properly is defective.
Common problems that cause Mercedes-Benz cruise control to stop working include:
- ABS sensor - On Mercedes-Benz vehicles, there is one ABS wheel speed sensor at each wheel. Any of them can fail and disable cruise control. In addition to cruise control, ABS, ESP, and stability control will also get disabled.
- Low battery voltage - Cruise control may disable if the voltage is too low. The battery may be too old, not holding a charge, and may need to be replaced. A dead battery can cause the cruise control inoperative warning as well.
- Defective steering angle sensor - It's mounted behind the steering wheel. It can lead to ABS light coming on and cruise control turning off. Try staring at the engine and turning the steering wheel full left to right a couple of times while in Park. This procedure can calibrate the steering angle sensor and could fix your cruise control.
- Faulty Sensors - Radar sensors behind the front bumper can get damaged or go bad on models equipped with Distronic.
- Defective brake light switch - Yes, a bad brake light switch can cause cruise control inoperative. You need to read the codes with a scanner as it is impossible to determine if the brake light switch is bad simply by looking at the brake lights.
- Engine misfire - If the check engine light is on, the vehicle may go in limp mode for several reasons, including cylinder misfire. The engine control unit (ECU) will turn off or prevent you from using cruise control to prevent further damage to the vehicle.
- Damaged wire harness - Wire harnesses that have been damaged during an accident.
- Poor ground connection - Corrosion can develop at ground points, especially on vehicles that have been in floods.
- MAF Sensor - A faulty mass airflow (MAF) sensor problem can cause the check engine light to come on, poor throttle response, brought idle, and a cruise control inoperative warning light to come on.
- Blown fuse - Of course, a blown a fuse can stop any system from working.
A diagnostic test is needed to determine what cruise control malfunction comes up on a Mercedes-Benz.
Perform a full system scan using a Mercedes-Benz scanner.