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Home >> Volvo >> 2008 >> V70 >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Charging System, Electrical Control Modules, Engine Control Module (ECM) - Design And Function >> Headlamp Control Module (HCM) (2008-09) >> System Overview >> Signals
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System Overview: Signals

The table below summarizes the input signals to and output signals from the headlamp control module (HCM). The signal types are divided into directly connected signals, serial communication and CAN communication. The graphic below displays the same information with the Volvo component designations.

Input signals: Output signals:
Directly connected:  Directly connected: 
  • Position sensor (7/119, 7/121)
  • Motor, headlamp levelling (not active headlamps)
Via serial communication:  Via serial communication: 
  • Left headlamp control unit (LHCU)/Right headlamp control unit (RHCU) (vehicles with active headlamps only)
  • Left headlamp control unit (LHCU)/Right headlamp control unit (RHCU) (vehicles with active headlamps only)
Via CAN communication:  Via CAN communication: 
  • Suspension module (SUM) (4/84)
  • Transmission Control Module (TCM) (4/28)
  • Brake control module (BCM) (4/16)
  • Engine control module (ECM) (4/46)
  • Steering wheel angle sensor module (SAS) (3/130)
  • Climate control module (CCM) (4/6)
  • Central electronic module (CEM) (4/56)
  • Driver information module (DIM) (5/1)
  • Climate control module (CCM) (4/6)
Fig 1: Identifying Input Signals To And Output Signals From Headlamp Control Module (HCM)
GLL179053Courtesy of VOLVO CARS CORPORATION