2002 Benz CLK430 ESP light comes on, how to solve?

Car model and year: 2002 Benz CLK430



As soon as the car cranks the BAS and ABS lights..Then after I drive for 100 ft the ESP light comes on.


Tool used:

Foxwell NT530 Benz scanner


Fault codes:

c1401: high pressure and return pump

c1000: ESP. SPS PML and BAS control unit


How to do:

A stored C1000 DTC indicates that the N47 Traction Control Module operation is not correct, which can be due to either a faulty module or system input or output.

A stored C1401 DTC indicates that power to the high pressure return pump (A7/3m1) is either a short or open circuit or will not shut off.

Following is a diagram showing the components associated with the W208 ABS/BAS/ESP system.

2002 Benz CLK430 ESP light comes on, how to solve?

Following are some troubleshooting suggestions that possibility could fix your issue for short money.

The N47 module is located in the passenger side fuse and relay box (K40/4) and power is provided via the 10 amp fuse in position 2.

As shown below, the power to the A7/3 hydraulic pump is provided from the F1 driver side fuse and relay box, by the 40 amp fuse in position 37.

2002 Benz CLK430 ESP light comes on, how to solve?


When checking these fuses, I would also pull them out of the socket and make sure that there is not corrosion/buildup between the fuse contacts and socket.

If the power through the fuse is OK, when called for, the voltage and current to run the A7/3 hydraulic pump passes through the switching contacts of the K40/2k4 relay, located in the F1 fuse box.

When switching high currents, relay failure is not so much caused by high inrush current upon motor startup, which can potentially weld the contacts together (upon which the motor will run continuously until you pull the 40 ampere fuse), but because it’s switching a highly inductive load (from the motor winding) and when the motor is switched off, the stored back emf causes a high voltage arc across the relay’s open contacts, which in time damages the contact surfaces, upon which the motor will not get the necessary current to operate reliability, or at all.

2002 Benz CLK430 ESP light comes on, how to solve?


Lastly, the S9/1 brake lamp switch has been a common problem regarding issues that cause a ABS/ESP/BAS trouble warnings. The switch actually has 2 separate circuits, one to turn on the rear stop lamps and the other to active the ABS/ESP/BAS system, whenever the brake pedal is pushed. If the circuit that activates on the ABS/ESP/BAS system does not function properly, due to improper plunger travel, a weak return spring etc., a warning will appear on the instrument cluster.

Hopefully, your issue is due to one of the above reasons, which are easy DIY repairs for short money.

The genuine MB OE relay is $15 or the Hella OEM part is $6. The genuine MB brake switch has been updated and is only around $20.


Good luck.