Road Speed Signal DDE 4.1

The ABS/ASC control unit transfers the current road speed to the DDE control unit.

The road speed serves as a measurement variable for following functions:

• Control condition for air conditioning system
  
• Limit volume calculation
  
• Injection volume calculation
  
• Vehicle speed control
  
• Gear recognition
  
• Idle speed control
  
• Engine mount control
  
• Electric fan control
  

Troubleshooting

If the signal is recognized as being faulty or the road speed as too high (> 250 km/h) or if the injection volume and engine speed infringe the plausibility, fault codes 0500 and 501 "road speed signal" are stored and a substitute value is output.

Consequences:

• Deactivation of vehicle speed control
  
• Switch off activation of engine mounts
  
• Deactivate A/C compressor