Road Speed Signal DDE 4.0

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

Fault code 0500 "Driving speed signal" is stored and a substitute value of 2.5 km/h is output if the signal is found to be faulty or the speed too high (> 250 km/h) or the plausibility is breached with injection volume and engine speed.

Consequences:

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