ABS/ ESP light came on on my 2000 E320 / Brake lights not working

First check to see if all the wheel speed sensors are reading. If one fails, it will deactivate several of these systems.

Brake light switch problem may cause the ESP / BAS lights to illuminate.

Common symptoms of a bad
Mercedes brake light switch.

• Car stuck in Park.
• ABS ESP ETS lights come on.
• Can not move the shifter from Park to Drive.
• Brakes Defective Warning on Instrument Cluster
• Car won't shift gears. Stuck in 2nd gear, limp mode.
• Brake lights don't work. (Brake light switch can still be defective even if the brake lights work. Checking the brake light operation is not a good test.)
• ESP, BAS, ABS lights turn on. Car won't shift properly. Stuck in gear.

TEST: To test your new brake light switch: Turn you car off to reset the ABS light. apply the parking brake. and start the car in neutral or park without using the brake. if the problem is the brake light switch... the light will only come on when you press the brake pedal.

If you replaced the brake light switch and the light is still on you should check a few other things such as:

• Fuses and Relays
• ABS pump
• ABS wheel speed sensor
• Brake Fluid Level
• Get an advanced scanner to read trouble codes.

NOTE: ** You may need a MBZ scan tool to reset the error code which was stored in the ECU because of the bad brake light switch.

There could be one or more of several reasons why the ESP light has illuminated on your Smart car...
For example, you could have a fault with dirty reluctor rings on the Abs system - faulty Abs sensor/ s ... a fault with the brake light switch - a fault with the steering angle sensor -- even a software glitch / issue in the control system...
The above are known issues that can and do cause the Esp light to come on.
What you will have to do is have the car connected to a dealer diagnostic machine - This will run a full diagnostic test and fault code read - to see why the Esp light has come on and quickly and efficiently find the right cause - and then it can be sorted out, whatever it transpires to be.
You really cannot do much on a Diy basis on these for this fault. You can check the reluctor rings as mentioned above and the wiring to the ABS sensors. The abs light will often come on to with the Esp light - but not always. Dont check these these things with the Ign On....
Too, you can check to see if the brake lights are working - if they are not - thats a definite indication of brake lamp switch failure which will cause the Esp light to come on - but while its worth checking - even if the lights do work - it doesn't always follow the switch is ok - it has a dual function - brake lights and engine management circuitry...
At which point, if you have found nothing - you will have to have the diagnostic done as above to find the fault.

MERCEDES BENZ DEALERSHIP HAS TO REPROGRAM THE ANTI LOCK BRAKE SYSTEM AND ELECTRONIC STABILITY CONTROL SYSTEM.IF YOU DISCONNECT BRAKE PAD WEAR SENSORS WHEN REPLACING BRAKE PADS. THE ABS BRAKES AND ESP SYSTEM HAS TO BE RESET TO TURN OFF ESP LIGHT.

Check & replace if necessary the brake pedal switch placed above pedals on the support.
If the problem still occurs you might access the ABS & ESP ECU (Electronic Control Unit) using diagnostic equipment connected to the data link connector of the car, in order to pull out all DTC (Diagnostic Trouble Codes) memored.
Then you will be able to replace bad piece(s) and fix the problem by erasing all DTC stocked inside ABS ECU & reset it.

The ESP system means the Electronic Stability Program. If the ESP lights on the dashboard permanently the ESP system is faulty. You must access the ESP Electronic Control Unit (ECU) memory for pull out all DTC (Diagnostic Trouble Codes), using diagnostic equipment connected to the data link connector of the car. Then you will be full informed about bad pieces (e.g.: brake pedal switch, front right wheel abs sensor interrupted, ...). After bad pieces replacement you will be able to erase all faults memored by ESP ECU, in other words reset the ESP system and turn off the warning lamp on dashboard.
I'm convinced that your brake pedal switch is faulty because the glow plug warning sign went ON after ESP warning light. Just replace the brake pedal switch, see if rear stop lamps light when press the brake pedal, and test the car on the road.
Good Luck!

Check first the third eye brake light. does it work? okay the problem reside in a ABS sensor make sure it is hook up or if you recently did a brake job it didnt get contaminated. When the ABS signal is interfered with ESP,Traction is disabled. One or some of the wheel speed sensor is disconnected or is being interfered with. This is common for a recent brake job if any occured

Either the system needs servicing or something has gone wrong with the brake system (YOU STILL HAVE REGULAR BRAKE OPERATION THOUGH). Check brake fluid, fuses, and try disconnecting the battery and leaving it for about a half hour. Hope this helps.

Check to see if your brake pads and rotors are in good condition. Or if you have replaced the pads yourself and have not reset the wheel sensors this would cause the ABS Antilock Brake System light and the ASC Automatic Stability Control light to stay on as the ASC uses the ABS brakes with computer assistance to control the car

yeah you mostlikey have a abs pressure switch problem. which helps in the power assist , and or the seal in the brake booster is going bad

Anti-Lock Control —Vehicles Built After 03/2002 The 3-channel anti-lock brake system consists of the following components:

• front wheel speed sensors
• front wheel speed sensor rings
• hydraulic control unit (HCU)
• Anti-lock brake control module (ECU)
• rear wheel speed sensor
• rear wheel speed sensor rings
• yellow anti-lock brake warning indicator

The 4-channel anti-lock brake system with traction control and stability assist system consists of the following components:

• active brake booster with integral solenoid
• brake booster release switch
• front wheel speed sensors
• front wheel speed sensor rings
• hydraulic control unit (HCU)
• stability assist module (ECU)
• stability assist event indicator
• lateral accelerometer
• longitudinal accelerometer (4x4)
• rear wheel speed sensors
• rear wheel speed sensor rings
• steering wheel position sensor
• yaw rate sensor
• yellow anti-lock brake warning indicator
• brake pressure transducer
• traction control switch

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I suspect the abs issue is causing the speed control not to work if it happened at the same time the cruise control stopped working. When the yellow ABS light comes on, it means the ABS is dactivated. You may have a faulty accelerometer which senses acceleration and yaw (side to side lean). I have not seen a bad one but you said it is sensitive to acceleration.
I would unplug it and see what happens. The connector should have a small tab to depress so you can pull the connector out.
Here is where it is:

Accelerometer Removal and Installation

1. NOTE: The accelerometer is located under the center, rear passenger seat carpet. (I think you have to remove seat for access).
   Cut the carpeting along the perforations.

1. Disconnect the electrical connector.

1. Remove the nuts and remove the accelerometer.

Have dealer hook up tester and pull fault codes if you can't find an easy solution.
Some background info

A malfunction in the anti-lock brake system will cause the anti-lock brake control module to shut off or inhibit the system. However, normal power-assisted braking remains.

Malfunctions are indicated by the yellow ABS warning indicator in the instrument cluster.

The anti-lock brake system is self-monitoring. When the ignition switch is turned to the RUN position, the anti-lock brake control module will carry out a preliminary self-check on the anti-lock electrical system indicated by a three-second illumination of the yellow ABS warning indicator in the instrument cluster.

During vehicle operation, including normal and anti-lock braking, the anti-lock brake control module monitors all electrical anti-lock functions and some hydraulic operations.

Each time the vehicle is driven, as soon as vehicle speed reaches approximately 20 km/h (12mph), the anti-lock brake control module turns on the pump motor for approximately one-half second. At this time, a mechanical noise may be heard. This is a normal function of the self-check by the anti-lock brake control module.

Pedal pulsation coupled with noise while braking on loose gravel, bumps, wet or snowy roads is normal and indicates correct functioning of the anti-lock brake system.

Warning Lamp Indicator
The anti-lock brake system (ABS) uses the yellow ABS warning indicator to alert the driver of a malfunctions in the ABS.
The yellow ABS warning indicator will come on to warn the driver that the ABS has been turned off due to a symptom that exists in the ABS. Normal power assist braking remains but wheels can lock during a panic stop while the yellow ABS warning indicator is illuminated.

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Please report back, I am curious if that is what it is. Good luck