Renewing the control unit

After the DSC control unit has been replaced, the following work must be performed in this order.

1. Coding

2. Calibration of the DSC sensors

• Steering angle sensor
  
• Rotation rate sensor
  
• Transverse acceleration sensor
  

3. End-of-line test (with driving curves without pressure sensor test)

The end-of-line test serves to check the DSC sensors in the plant at the end of the assembly line. This test is active on every factory-new DSC control unit and it must therefore also be run every time a factory-new DSC control unit is fitted.

Procedure for end-of-line test:

The sequence varies depending on the vehicle model and control-unit version. Due to the identification of the DSC control unit by the DIS tester, the following procedure results.

• Disconnect the diagnostic plug to exit from the diagnostic mode.
  If all indicator lamps have gone out on exiting the diagnostic mode, the end-of-line test has been carried out automatically by the control unit. No other work is then required. This is the case for control units of later dates of manufacture
  
• Bring the vehicle into a position that allows driving forwards in a curve.
  
• Switch off the ignition for at least 10 seconds to perform a reset of the DSC.
  
• Start the engine.
  
• Standstill calibration: After the engine start-up, the DSC and ABS indicator lamps light up (the end-of-line test is active). After approx. 2 seconds, the DSC indicator lamp goes out.
  
• Check of the rotation rate and transverse acceleration sensor: Drive in a curve with a small radius; the ABS indicator lamp goes out.
  

Faults during end-of-line test:

If the end-of-line test is not concluded successfully (one or both indicator lamps light up), the DSC is not working and at least the fault ”6D end-of-line test not carried out” is entered in the fault code memory with the status ”currently present”.

• The DSC indicator lamp does not go out after approx. 2 seconds.
  The DSC has not run a reset or there is a fault. Switch off the ignition again for at least 10 seconds. If this does not lead to a reset, the reset can also be forced by briefly disconnecting the fuse of the DSC power supply via terminal 87. If DSC indicator lamp still does not go out after this, the fault must be pinpointed.
  
• The ABS indicator lamp goes not go out and the DSC indicator lamp lights up again.
  The end-of-line test must be repeated. If the end-of-line test fails a second time, it is likely that there is a fault in the area of the rotation rate and transverse acceleration sensor. Run troubleshooting.