System Operation: CTA
When the transmission is in reverse, the CTA system can detect a vehicle or a bicycle that is approaching at a speed between 8 km/h and 60 km/h (5 mph and 37 mph) and time to impact is between 1 and 2.5 seconds. The CTA system illuminates a LED in the outside mirror on the side of your vehicle the approaching vehicle is coming from. The CTA system also sounds an audible alert and a message appears in the information display or a warning indicator displays in the enabled driver information HUD area (if equipped and enabled by the driver), indicating a vehicle is coming from the right or left. The distance at which an alert is generated varies depending on the speed of the approaching vehicles or bicycles. The CTA system response time and performance can degrade if vehicles are approaching at speeds greater than 60 km/h (37 mph).
An adjacent parked vehicle or object can affect the systems ability to detect approaching vehicles or bicycles (refer to the first figure below). Parking at extreme angles can further affect the systems ability to detect approaching vehicles or bicycles (refer to the second figure below). Backing towards a curve road can also affect systems ability to detect approaching vehicles or bicycles (refer to the third figure below).
CTA detection zones:
The CTA system is designed to detect objects approaching the vehicle at a speed equal to or greater than 8 km/h (5 mph). This includes vehicles and bicycles. The CTA system has some detection limitations due to the nature of the radar technology used by the SODL and SODR.
Circumstances that may cause non-detection are:
- Debris build-up or bumper stickers on the rear bumper sides
- The rear quarter panel of the vehicle is obstructed or partially obstructed by an adjacently parked vehicle or object
- Vehicle approaching at speeds greater than 60 km/h (37 mph)
- Driving in reverse faster than 12 km/h (8 mph)
- Damage to sensor and/or sensor area
Due to the nature of radar technology, there may be certain instances when the CTA system alerts the operator, when no object or vehicle is present while backing up. This is known as a false alert. False alerts up to 3% of the time (3 times out of 100 reversals) are considered normal. A false alert may occur when backing out of a garage or backing into a parking space and objects or vehicles are very close to the radar sensors. False alerts are temporary and self-correcting.
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 bumper stickers on the rear bumper sides
- Certain maneuvering of the vehicles entering and exiting the detection zone
- Vehicles passing through the detection zone at high rates of speed
- When several vehicles forming a convoy pass through the detection zone
Exterior Mirror Indication
When the BLIS ® or CTA system is active and an object is detected by the SODL or SODR, the BLIS ®/ CTALED command message is sent from the SODL or SODR to the DDM or PDM. The DDM and PDM supply voltage and ground to illuminate their respective exterior mirror BLIS ®/ CTALED based on messages received from the SODL and SODR. There are two BLIS ®/ CTALED brightness levels, full illumination (daytime condition) and dimmed illumination (nighttime condition). The DDM and PDM control their respective exterior mirror BLIS ®/ CTALED brightness level based on a day/night message received from the BCM over the HS-CAN1 through the GWM.
Each time the vehicle is started, the SODL and SODR command the DDM and PDM to illuminate the exterior mirror BLIS ®/ CTA Light Emitting Diodes (LEDs) for approximately 3 seconds, indicating the BLIS ® and CTA system is operational.
If a BLIS ® or CTA system fault is present, the exterior mirror BLIS ®/ CTA Light Emitting Diodes (LEDs) remain off, the IPCBLIS ® RTT illuminates and a message center warning displays BLIND SPOT SYSTEM FAULT.