Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Blind Spot Information System - System Operation and Component Description: Notes
System Operation
BLIS® and CTA
System Diagram
Network Message Chart
IPC Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| BLIS trailer tow left status | SODL | Used to communicate the operating status of the SODL and to command the BLIS®. |
| BLIS trailer tow right status | SODR | Used to communicate the operating status of the SODR and to command the BLIS®. |
| Cross traffic alert left status | SODL | Used to command the CTA audio chime and the BLIS® RTT. |
| Cross traffic alert right status | SODR | |
| Side obstacle sensor status - left | SODL | Used to communicate the operating status of the SODL and to command the CTA message center displays. |
| Side obstacle sensor status - right | SODR | Used to communicate the operating status of the SODR and to command the CTA message center displays. |
ACM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Chime source | IPC | Used to command the all audio chimes on without touchscreen. |
DSP Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Chime source | IPC | Used to command the all audio chimes on vehicles with touchscreen. |
DDM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Cross traffic alert left status | SODL | Used to command the LHBLIS®/ CTALED on and off. |
| Side obstacle sensor status-left | SODL | Used to command the LHBLIS®/ CTALED on and off. |
| Side detect left illumination | SODL | Used to command the LHBLIS®/ CTALED on and off. |
PDM Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| Cross traffic alert right status | SODR | Used to command the RHBLIS®/ CTALED on and off. |
| Side obstacle sensor status-right | SODR | Used to command the RHBLIS®/ CTALED on and off. |
| Side detect right illumination | SODR | Used to command the RHBLIS®/ CTALED on and off. |
SODL Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| BLIS® LED status driver side | DDM | Used to confirm the operating status of the LH exterior mirror BLIS® LED. |
| BLIS®/ CTA enable/disable command | IPC | Used to enable/disable the BLIS® or CTA based on driver input. |
| Ignition key type | BCM | Used to disable the ability to turn off the BLIS® and CTA when a MyKey® restricted key is in use. |
| Gear lever position | PCM | Used to turn the BLIS® and CTA system on and off depending the gear lever position. |
| Front wiper status | SCCM | Used to determine ambient weather conditions for correct system operation. |
| Turn signal switch status | SCCM | Used to generate the secondary alert when a turn signal is activated. |
| Trailer lamp connected | TRM | Disables the BLIS® and CTA when a trailer is electrically connected to the vehicle. |
| Vehicle speed | PCM | The vehicle speed input is used to turn the BLIS® on above 10 km/h (6 mph). |
SODR Network Input Messages
| Broadcast Message | Originating Module | Message Purpose |
|---|---|---|
| BLIS® LED status driver side | PDM | Used to confirm the operating status of the RH exterior mirror BLIS®) LED. |
| BLIS®/ CTA enable/disable command | IPC | Used to enable/disable the BLIS® or CTA based on driver input. |
| Ignition key type | BCM | Used to disable the ability to turn off the BLIS® and CTA when a MyKey® restricted key is in use. |
| Gear lever position | PCM | Used to turn the BLIS® and CTA system on and off depending the gear lever position. |
| Front wiper status | SCCM | Used to determine ambient weather conditions for correct system operation. |
| Turn signal switch status | SCCM | Used to generate the secondary alert when a turn signal is activated. |
| Trailer lamp connected | TRM | Disables the BLIS® and CTA when a trailer is electrically connected to the vehicle. |
| Vehicle speed | PCM | The vehicle speed input is used to turn the BLIS® on above 10 km/h (6 mph). |
BLIS®
The BLIS® provides alerts to the driver when the vehicle is in a forward gear and the vehicle speeds is greater than 10 km/h (6 mph).
The BLIS® can trigger an alert for vehicles that enter the blind zone from the rear, front, or merge into the blind zone from the side. The exterior mirror BLIS®/ CTALED illuminates in the right and/or left exterior mirror when a target is present. For vehicles that pass through the blind zone quickly, typically less than 2 seconds, the BLIS® may not trigger an alert.
If a turn signal is active while BLIS® has detected a target in the blind zone, the BLIS®/ CTALED flashes rapidly. When the turn signal is off, the BLIS® target warnings are a constant LED illumination.
Due to the nature of radar technology, false alerts may occur under certain circumstances. False alerts occur when the LED illuminates with no target present. False alerts up to 3% (3 out of 100 targets) is considered normal operation. False alerts are temporary and self-correcting. False alerts may be caused by sharp turns around a pole or building, jogging pedestrians or fast moving shopping carts.
Missed targets occur when a target is present and the LED does not illuminate. Missed targets up to 1% (1 out of 100 targets) is considered normal operation.
Circumstances that cause missed alerts are:
- Debris build-up or damage to the rear lamp assemblies
- Certain maneuvering of the vehicles entering and exiting the blind zone
- Vehicles passing through the blind zone at high rates of speed
- When several vehicles forming a convoy pass through the blind zone
The BLIS® may not detect an adjacent target immediately when the vehicle accelerates from a standing start with another vehicle alongside.
BLIS® with Trailer Tow (BTT)
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.