Glowplug system DDE6.0

The glow plug system consists of the following components:

• DDE control module
  
• electronic glow plug control module
  
• quick-start glow plugs
  
• Bit serial data interface (BSD) and electrical leads
  

No glow-duration relay is installed.

The quick-start glowplugs are designed for a voltage of between 5.3 and 7.8 Volts. In the initial heating stage, system voltage may also be applied for a short time.

The essential differences from the glow plug systems on previous models are as follows:

• control of the glow plugs is by pulse width modulation
  
• the glow plug relay has been dispensed with and its function taken over by electronic output stages on the glow plug control module
  
• an emergency glow plug function has been introduced
  
• quick-start glow plugs have been introduced
  
• each of the four glow plug circuits can be diagnosed individually
  

To check the glow system, there are two adapter leads:

• 1-pin, order number 13 6 470
  
• 12-pin, order number 13 6 460
  In conjunction with measurement box 26-pin, order number 61 1 459
  

Function

The glow plug control module communicates with the DDE control module via the bit serial data interface.

The required heating output is determined by the DDE control module on the basis of the following operational parameters:

• Coolant temperature
  
• Vehicle voltage
  

Two other operational parameters determine the point at which glow plug function is activated and deactivated:

• Engine speed
  
• Injection volume
  

The DDE control module transmits the heating request to the glow plug control module via the bit serial data interface. The glow plug control module puts the request into effect by activating the glow plugs by means of a pulse-width modulated signal. In addition, the glow plug control module sends diagnostic and status information back to the DDE control module.

Preheating

At coolant temperatures below 25 °C, there is a preheating period of 0.5 seconds. The preheating period increases as the temperature falls, reaching a maximum of 2.7 seconds at a coolant temperature of less than -25 °C.

Activation of the glow plug system on the instrument cluster only occurs at coolant temperatures below 0 °C.

After-heating

At coolant temperatures below 30 °C, there is a temperature-dependent after-heating period to improve idling and exhaust emission characteristics.

Start preheating

Start preheating takes place for approx. 10 seconds if after the preheating time has elapsed the engine is not started and the ignition remain on.

Troubleshooting

The DDE control module monitors communication with the glow plug control module. In the event of a fault on the bit serial data interface, the DDE control module stores the following fault code:

• 4203, Glow plug control module, no communication via bit serial data interface
  

The glow plug control module monitors activation of the individual glow plugs and is able to detect the following faults and store them for each glow plug:

• Short circuit to ground
  
• Break
  
• Excess temperature output stage
  

If the glow plug control module detects a fault, it reports it to the DDE control module which stores the fault in its fault memory.