Wiring diagram of OEM 8HP TCM CAN control for GCU, IO CAN and IO Pro
Using HTG OEM TCM control strategy wiring is greatly simplified compared to standalone control. Below sections describe necessary connections.
Connector and terminals as well as premade wiring looms can be obtained at shop.htg-tuning.com or via our SALES email.
| ZF 8HP connector | HTG IO CAN | comments |
|---|---|---|
| 8HP: 1 | ||
| 8HP: 2 | ||
| 8HP: 3 | IOC 18: PT_CAN_2_Lo | termination needed, 0,35mm2 / 22AWG |
| 8HP: 4 | IOC 5: PT_CAN_2_Hi | termination needed, 0,35mm2 / 22AWG |
| 8HP: 5 | IOC 6: PT_CAN_1_Hi | termination needed, shared with OBD, 0,35mm2 / 22AWG |
| 8HP: 6 | IOC 19: PT_CAN_1_Lo | termination needed, shared with OBD, 0,35mm2 / 22AWG |
| 8HP: 7 | ||
| 8HP: 8 | ||
| 8HP: 9 | IOC 2: +12v wake-up | 0,5mm2 / 22AWG |
| 8HP: 10 | ||
| 8HP: 11 | ||
| 8HP: 12 | ||
| 8HP: 13 | IOC 1: +12v MAIN | external source, 2mm2 / 15AWG |
| 8HP: 14 | IOC 14: GROUND | chassis, 2mm2 / 15AWG |
| 8HP: 15 | ||
| 8HP: 16 |
PT_CAN Both CAN buses require proper termination according to their design. Using HTG GCU each CAN bus shall have 120R resistors installed at both ends between Hi and Lo, using HTG IO CAN termination is enabled in the software. Measured value across Hi to Lo should be 60 ohm. Wires should be twisted and as short as possible to reduce packet loss probability. 8HP CAN_1 is shared with OBD port optionally.
+12v wake-up IGNITION signal that is present with key ACC, ON and CRANK positions. No fuse required. Same source can be used to power up HTG GCU / IO Pro and shifter if required.
+12v MAIN Main power connection. Protected with 15A fuse or 15-20A PDM setting. +12 MAIN HAS TO BE PRESENT with ACC, ON, CRANK key positions and OFF position for at least 60-90 sec period. Timed shutoff is require to allow OEM TCM save corrections. Can be permanent
GND Good quality chassis / engine grounding point.
OBD port is connected to CAN1 (PT_CAN_1). Obd plug wiring can be found in separate article
ALL REMAINING I/O As per HTG GCU instructions.
