Our wiring kit covers all necessary connections to allow GCU fully control desired transmission.
Each of our kits has second branch of wires – those have to be connected to certain points in the car.

  • 2x GCU +12v_const (M3, M4) labeled as “BAT+” (red wires). It’s main power supply for GCU and transmission. Wire to main relay (switched ON at ignition-on) secured with 30A fuse
  • 1x GCU +12_IGN (L1) labeled as “L1” (red wire). It’s ignition signal that wakes-up GCU.
  • 2x GCU GND (L3, L4) labeled as “GND” (black wires). It’s power ground connection. Make sure that ground point is a reliable one. Chassis or drivetrain (engine/transmission) are also good ground points 🙂
  • 1x GCU +5_out (M1) labeled as “GCU 5v” (red wire). It’s 5v supply for SENSORS used with GCU (f.eg. clutch potentiometers, paddle’s pull-ups) . DO NOT USE THIS OUTPUT TO POWER ANY DEVICES.
  • 1x GCU sGND (L2) labeled as “sGND” (black wire). It’s sensor ground reference. Used to connect to sensors and it’s shields. This sensor ground CANNOT be joined with power grounds (L3, L4)
  • CAN_1_Hi (G1) and CAN_1_Lo (G2).  CAN-bus 1 connection for communication with other devices like dashes, ECUs. If GCU is at end of the bus 120R resistor  has to be used as terminator. Second CAN-bus can be added (G3, G4).
  • 1x GCU PWR_out12 (K4) labeled as “K4” (green or gray wire). It’s spare power output (high or low side). Depending on transmission configuration more than 1 spare output may be available, 1 is prewired as standard. This output can be used to connect for example reverse light.
  • 3x GCU AN_in9, AN_in10, AN_in11 (E2, E3, E4). Analog inputs for sensor connections like paddles, potentiometer, switches.