Low Speed GMLAN Circuit Description
| Callout | Component Name |
|---|---|
| DD8 | MIRROR I/S R/V: LT SENSITIVE |
| UE1 | COMMUNICATION SYSTEM: VEHICLE, ONSTAR |
| ULS | STEERING COLUMN LOCK: MECHANICAL |
| UVF | CAMERA: FRONT MODULE (DO NOT USE AFTER MY15) |
| X84 | X84 Data Link Connector |
| A10 | A10 Inside Rearview Mirror |
| K73 | K73 Telematics Communication Interface Control Module |
| K9 | K9 Body Control Module |
| K60 | K60 Steering Column Lock Module |
| P17 | P17 Info Display Module |
| A11 | A11 Radio |
| K33 | K33 HVAC Control Module |
| P16 | P16 Instrument Cluster |
| K161 | Vehicle Performance Data Recorder |
| K36 | K36 Inflatable Restraint Sensing and Diagnostic Module |
| K84 | K84 Keyless Entry Control Module |
| K85 | Passenger Presence Module |
| K23 | K23 Folding Top Control Module |
| K40P | Seat Memory Control Module - Passenger |
| K40D | K40D Seat Memory Control Module - Driver |
| T3 | T3 Audio Amplifier |
Low Speed GMLAN Bus is used in applications where a high data rate is not required which allows for the use of less complex components. It is typically used for operator controlled functions where the response time requirements are slower than those required for dynamic vehicle control.
The Low Speed GMLAN Serial Data Network consists of a single wire, ground referenced bus with high side voltage drive. During on road vehicle operation data symbols (1's and 0's) are transmitted sequentially at the normal rate of 33.3 Kbit/s. For component programming only, a special high speed data mode of 83.3 Kbit/s may be used.
Unlike the high speed dual wire networks, the single wire low speed network does not use terminating resistors at either end of the network.
The data symbols to be transmitted over the bus are represented by different voltage signals on the bus. When the Low Speed GMLAN Bus is at rest and is not being driven, there is a low signal voltage of approximately 0.2 V. This represents a logic "1". When a logic "0" is to be transmitted, the signal voltage is driven higher to around 4.0 V or higher.