Roadspeed signal DDE 5.0/5.1

The vehicle's current road speed is signalled to the DDE control unit by the ABS/ASC control unit via the CAN bus.

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

• Control condition for air conditioning system
  
• Oil pressure warning lamp activation condition
  
• Limit volume calculation
  
• Injection volume calculation
  
• vehicle speed control
  
• Gear recognition
  
• Idle speed control
  
• Electric fan control
  

Troubleshooting

If a fault is detected in the signal received via the CAN bus, the following fault code is stored:

• 3F62, Road speed signal from CAN invalid
  

In addition, the signal is also checked for plausibility and monitored for the following faults:

• 3F50, Road speed too high
  
• 3F52, Invalid signal
  
• 3F50, Plausibility in conjunction with injection volume and engine speed