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Auxiliary heater heating mode > < Requirements for the sequence described on the following pages

Sequence for activating auxiliary heating

Activation of auxiliary heating
Activation of auxiliary heating
  Note
Vehicles with diesel engines (including those fitted with an auxiliary heater as optional extra) are currently provided with a supplementary air heater element -Z35- → Air conditioning; Rep. Gr.87. On vehicles with a supplementary air heater element -Z35- and fitted with an auxiliary heater, this is not actuated as supplementary heater (discontinuation of the supplementary air heater element -Z35- on vehicles fitted with an auxiliary heater as optional extra has not yet been finalised).
   
No.Operating sequence
1ON signal
 Auxiliary heating:
l  Signal from operating and display unit, Climatronic control unit -J255- (via data bus, setting is made on MMI).
l  Signal from auxiliary heating radio controlled receiver -R64-.
l  Signal from vehicle diagnostic, testing and information system -VAS 5051/- (by way of basic setting function).
–  Operating and display unit, Climatronic control unit -J255- interrogation (by way of data bus).
 Supplementary heater (for vehicles with diesel engine without supplementary air heater element -Z35- only):
l  Signal from operating and display unit, Climatronic control unit -J255- (by way of data bus).
l  Signal from vehicle diagnostic, testing and information system -VAS 5051/- (by way of basic setting function).
2Initiation of starting .
 Auxiliary heating:
l  The operating and display unit, Climatronic control unit -J255- decides that heating mode is required to attain the specified temperature in the passenger compartment.
–  Checking of measured values and components by way of interrogation of event recorder, power supply, coolant temperature and checking of all electrical components and input signals → Chapter.
–  Initiation of starting.
 Supplementary heater (for vehicles with diesel engine without supplementary air heater element -Z35- only):
–  Checking of measured values and components by way of interrogation of event recorder, power supply, coolant temperature and checking of all electrical components and input signals → Chapter.
–  Initiation of starting.
 Possible deviations, starting is not initiated.
 Auxiliary heating:
l  The operating and display unit, Climatronic control unit -J255- decides that heating mode is not required to attain the specified temperature in the passenger compartment.
–  Auxiliary ventilation (summer mode) → Chapter.
3Start
 3.1Starting (diesel)
  
l  No deviations in measured values and components monitored → Chapter.
  
–  Actuation of circulation pump -V55- and heater coolant shut-off valve -N279-.
–  Voltage at combustion air blower -V6- for brief period.
–  Voltage at glow plug for heater -Q9-.
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated).approx. 8 V5 sec.
  Metering pump -V54- (regulated).0 Hz-
  Glow plug for heater -Q9-.8 V35 sec.
  
–  Activation of combustion air blower -V6- (supply).
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated).approx. 8 V7 sec.
  Metering pump -V54- (regulated).0 Hz-
  Glow plug for heater -Q9-.8 V7 sec.
  
–  Reduction in voltage at combustion air blower -V6-.
–  Activation of metering pump -V54- (fuel pre-supply, regulated, start-up sequence).
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated).6 to 4 V26 sec.
  Metering pump -V54- (regulated).approx. 4 Hz26 sec.
  Glow plug for heater -Q9-.approx. 8 V26 sec.
  
–  Increase in voltage at combustion air blower -V6- (monitoring time).
–  Slight increase in regulation at metering pump -V54- (fuel pre-supply, regulated).
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated).4 to 9 V37 sec.
  Metering pump -V54- (regulated).4 to 5 Hz37 sec.
  Glow plug for heater -Q9- (pre-heating, regulated).8 V37 sec.
  
–  Slight increase in voltage at combustion air blower -V6- to full load.
–  Increase in clock frequency of metering pump -V54- to full load.
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated).approx. 9 V15 sec.
  Metering pump -V54- (regulated).5 to 8 Hz15 sec.
  Glow plug for heater -Q9- (pre-heating, regulated).8 V15 sec.
  
–  Combustion air blower -V6- set to full load.
–  Clock frequency of metering pump -V54- set to full load.
–  Deactivation of glow plug for heater -Q9- (start of full load mode).
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated).approx. 9 Vapprox. 45 sec.
  Metering pump -V54- (regulated).approx. 6 Hzapprox. 45 sec.
  Glow plug for heater -Q9- (flame monitoring).0 V-
  
–  Start of heating operation → Chapter.
 3.2Starting (petrol)
  
l  No deviations in measured values and components monitored → Chapter.
  
–  Signal for actuation of circulation pump -V55- and heater coolant shut-off valve -N279-.
–  Voltage at combustion air blower -V6- for brief period.
–  Voltage at glow plug for heater -Q9-.
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated).approx. 8 V5 sec.
  Metering pump -V54- (regulated).0 Hz-
  Glow plug for heater -Q9- (pre-heating, regulated).approx. 8 V5 sec.
  
–  Increasing voltage at combustion air blower -V6- (supply).
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated).0 to 2 V40 sec.
  Metering pump -V54- (regulated).0 Hz-
  Glow plug for heater -Q9- (pre-heating, regulated).approx. 8 V40 sec.
  
–  Brief activation of metering pump -V54-.
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated). approx. 2 V5 sec.
  Metering pump -V54- (regulated).approx. 4 Hz5 sec.
  Glow plug for heater -Q9- (pre-heating, regulated).approx. 8 V5 sec.
  
–  Increasing voltage at combustion air blower -V6-.
–  Increase in clock frequency of metering pump -V54- to full load.
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated).2 to 4 V18 sec.
  Metering pump -V54- (regulated).2 to 3 Hz18 sec.
  Glow plug for heater -Q9- (pre-heating, regulated).approx. 8 V18 sec.
  
–  Increase in voltage at combustion air blower -V6-.
–  Increase in clock frequency of metering pump -V54- (start-up sequence).
–  Reduction of voltage at glow plug for heater -Q9-.
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated).4 to 8 V17 sec.
  Metering pump -V54- (regulated).3 to 6 Hz17 sec.
  Glow plug for heater -Q9- (pre-heating, regulated).approx. 8 V17 sec.
  
–  Increase in clock frequency of metering pump -V54-.
–  Deactivation of glow plug for heater -Q9-.
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated).8 V20 sec.
  Metering pump -V54- (regulated).6 to 7 Hz20 sec.
  Glow plug for heater -Q9-.0 V-
  
–  Slight increase in voltage at combustion air blower -V6- to full load. (monitoring time)
–  Increase in clock frequency of metering pump -V54- to full load (start of full load mode).
  Components Actuation
with		Duration
approx.
  Combustion air blower -V6- (regulated).approx. 9 Vapprox. 45 sec.
  Metering pump -V54- (regulated).7 to 8 Hzapprox. 45 sec.
  Glow plug for heater -Q9- (pre-heating, regulated).0 V-
  
–  Start of heating operation → Chapter.
3.3Possible deviations, starting is not initiated.
 
l  Deviation in measured values and components monitored. By interrogation of event recorder, power supply, coolant temperature and checking of all electrical components and input signals → Chapter.
–  Termination of starting.
 
l  Resistance of flame monitor -G64- outside specified range → Chapter.
–  Termination of process (1 x start repetition).
 
l  Resistance of glow plug for heater -Q9- outside specified range even after start repetition. Interrogation of resistance of glow plug for heater -Q9- (remains hot) → Chapter.
–  Termination of procedure (entry in event recorder)/fault/off.

  Note
t  Actuation of heater coolant shut-off valve -N279-, regulated as a function of temperature → Chapter.
t  The operating and display unit, Climatronic control unit -J255- is switched on by the auxiliary heater control unit -J364- as soon as the coolant temperature in the auxiliary heater exceeds a value of approx. 40 ...50 °C. The exact cut-in temperature depends on the version of the auxiliary heater. The operating and display unit then actuates the various air conditioner control motors and the fresh air blower -V2- in auxiliary heating mode → Vehicle diagnostic, testing and information systemVAS 5051/, “Guided fault-finding function”.
   

Auxiliary heater heating mode > < Requirements for the sequence described on the following pages