MG 4 Gear Selector
General Information
MG 4 uses a rotary gear selector.
Neutral corresponds to the central rest postion, Reverse is selected by an anticlockwise twist, Drive by clockwise rotation of the gear knob.
Park is selected by pressing the gear knob.
Selected gear is communicated by CAN.
The unit incorporates three LEDs across the top of the unit which correspond to Reverse, Neutral and Drive.
The knob itself lights up in Yellow when Park is selected.
Part Numbers
SAIC Motor Shift-by-wire : 11357121
Pinout and Connector
The shifter uses a 12 way connector, of which only 5 pins are connected.
Required plug is:
Molex 347290122 : https://www.molex.com/en-us/products/part-detail/0347290122
When viewed from the rear of the unit, Pin1 is top-left, Pin12 is bottom right.
| Pin | OEM Wire Colour | Function |
|---|---|---|
| 1 | Black/Yellow | 12V |
| 5 | Pink/White | 12V WakeupEnable |
| 7 | Yellow/Blue | PT-CAN Ext High |
| 8 | Green/Yellow | PT-CAN Ext Low |
| 12 | Black | GND |
CAN Bus
The Powertrain CAN Bus has a baud rate of 500kBaud.
Most messages have a standard CRC-8-SAE J1850. (polynomial 0x1D)
| CanId | Message | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|---|---|
| 0x09D | Shifter Status (from Shifter) | CRC8 (bytes1-7) | Counter 4-bit
F0-FF |
03 | POS1 | POS2 | F0|F1 | 38|39 | FF |
| 0x047 | Msg1 from Controller | CRC8 (bytes1-7) | Counter 4-bit
00-0F |
45 | 9B | 7F | FF | FF | FE|FF |
| 0x12a | Msg2 from Controller | CRC8 (bytes1-7) | Counter 4-bit
F0-FF |
FF | FF | FF | FF | FF | 01|11|13|14 |
| 0x2b6 | Msg3 from Controller | 00 | 00 | 02 | 00 | 00 | 00 | 00 | 00 |