Principles Of Operation
Blind Spot Monitoring
Principles of Operation
NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
NOTE: If the vehicle is towing a trailer, the Blind Spot Information System (BLIS(TM)) or Cross Traffic Alert (CTA) system might detect the trailer, causing a false alert.
NOTE: The BLIS(TM) and CTA system both utilize the Side Obstacle Detection Control Module - Left (SOD-L), Side Obstacle Detection Control Module - Right (SOD-R) and the exterior mirror BLIS(TM)/CTA LEDs.
The SOD-L and SOD-R run a self diagnostic check on each vehicle start cycle and illuminate the exterior mirror BLIS(TM)/CTA amber LED for approximately 3 seconds indicating that the BLIS(TM) and CTA system is operational. For BLIS(TM), the exterior mirror BLIS(TM)/CTA LED is at 95 percent illumination to be seen clearly during the day and is dimmed down to 10 percent at night. For the CTA system, the exterior mirror BLIS(TM)/CTA LED is always at 85 percent illumination.
Blind Spot Information System (BLIS(TM))
When the vehicle is started, both exterior mirror BLIS(TM)/CTA amber LEDs briefly illuminate to indicate that the system is operating. If a BLIS(TM) fault is present, the LEDs remain illuminated and a message in the Instrument Panel Cluster (IPC) message center displays "BLIND SPOT SYSTEM FAULT". System faults can occur that cause the associated left or right exterior mirror BLIS(TM)/CTA amber LED not to illuminate; only the IPC message center message fault is displayed.
BLIS(TM) becomes active the first time the transaxle is placed in DRIVE (D) after starting the engine and driving forward at a vehicle speed greater than 5 km/h (3 mph). Upon that initial sequence, BLIS(TM) remains active for all speeds including 0 km/h (0 mph). BLIS(TM) is also active if the transaxle is placed in NEUTRAL (N). If the transaxle is selected out of DRIVE (D) or NEUTRAL (N) the system has entered the CTA mode. When the transaxle is shifted back into DRIVE (D), BLIS(TM) is activated once the vehicle is driven above 5 km/h (3 mph).
NOTE: BLIS(TM) does not normally detect parked vehicles, pedestrians or objects such as fences, guard rails, trees, etc.BLIS(TM) does not provide any additional warning when the turn signal is activated.
BLIS(TM) can trigger an alert for vehicles that enter the blind zone from the rear or merge into the blind zone from the side. The exterior mirror BLIS(TM)/CTA amber LED illuminates in the right and/or left exterior mirror. For vehicles that are being passed or vehicles that enter the blind zone from the front, the system can trigger an alert only after the vehicle is present in the blind zone for more than 2 seconds. For vehicles that pass through the blind zone quickly, typically less than 2 seconds, BLIS(TM) cannot trigger an alert.
BLIS(TM) utilizes 2 modules that have integral radar sensors located rearward of the rear wheel under the rear bumper cover. The 2 modules, SOD-L and SOD-R, are hardwired to the exterior mirrors to illuminate the LEDs. For correct operation of BLIS(TM), the rear side bumper cover should be free of obstructions such as a large build up of mud, snow or ice. Small build up of debris and materials does not hinder the operation of the system. There should be no bumper stickers of any type placed in this area of the bumper cover.
Due to the nature of radar technology, false alerts and missed targets may occur under certain circumstances. False alerts are when the LED illuminates with no target present. False alerts up to 3% (3 out of 100 targets) is normal operation. Circumstances that cause false alerts are freeway divider, concrete walls, cyclone fencing, sharp turns around a pole or building and coming to a stop with a vehicle directly behind and very close. False alerts are temporary and self-correct.
Missed targets are when a target is present and the LED does not illuminate. Missed targets up to 1% (1 out of 100 targets) is normal operation. Circumstances that cause missed targets are:
- Debris build up on the rear quarter panel fascias
- Certain maneuvering of vehicles entering and exiting the blind zone
- Vehicles passing through the blind zone at very fast rates
- Severe weather conditions
- When several vehicles forming a convoy pass through the blind zone
The exterior mirror indicators may not operate correctly when the vehicle accelerates from a standing-start with a vehicle alongside.
BLIS(TM) can be turned off by selecting the blind spot ON/OFF function in the message center. BLIS(TM) is turned off in the IPC by selecting the blind spot system with the SETUP switch for the message center and selecting the system on or off with the RESET switch. The message "BLIND SPOT SYS OFF" is displayed in the message center. When turning BLIS(TM) from on to off or off to on, the exterior mirror BLIS(TM)/CTA amber LEDs flash twice. When BLIS(TM) is off, the driver cannot receive any alerts. The system is reactivated on the next ignition cycle.
BLIS(TM) can be disabled permanently (even after an ignition cycle) by using a scan tool. When using the scan tool disable function in the programmable parameters menu, BLIS(TM) remains disabled until it is reactivated using the scan tool. When the system is disabled the IPC message center displays "BLIND SPOT DISABLED". A system fault occurs if BLIS(TM) is not disabled in both the SOD-L and the SOD-R.
There are some system faults that can set DTCs which are logged in the SOD-L or SOD-R. These DTCs can set a message in the IPC message center that displays "BLIND SPOT SYSTEM FAULT". There are also symptom based faults that do not set a DTC. GO to Symptom Chart. Blind Spot Monitoring
Cross Traffic Alert (CTA) System
NOTE: The BLIS(TM) and CTA system both utilize the SOD-L, SOD-R and the exterior mirror BLIS(TM)/CTA LEDs.
NOTE: The CTA system faults may not occur until the transaxle is placed in REVERSE (R).
The CTA system is an alert feature that assists the driver in backing out of a front-in parking space. When the transaxle is in REVERSE (R) the CTA system is active. The driver is warned of an approaching vehicle when an audio alert chime from the parking aid speaker sounds, the right or left exterior mirror BLIS(TM)/CTA amber LED flashes, and the Instrument Panel Cluster (IPC) message center displays "VEHICLE COMING FROM RIGHT or VEHICLE COMING FROM LEFT" to warn the driver from which direction vehicles are approaching.
The CTA system detects a vehicle approaching up to 14 m (45 ft) away (approximately the width of 5 parking spaces). Backing out of parking spots slowly increases the radar sensor coverage in close proximity situations. The CTA system coverage also decreases when parking at shallow angles, which is described in the Owner's Literature.
The CTA system utilizes the same SOD-L and SOD-R as BLIS(TM).
The CTA system cannot normally detect stationary vehicles, humans, animals or objects such as fences, guard rails or trees. The system does not function when the transaxle is not in REVERSE (R).
The CTA system has detection limitations due to the nature of the radar technology for the SOD-L and SOD-R. There can be certain instances where vehicles entering and exiting the blind spot zone may not be detected. The circumstances that may cause non-detection are:
- Debris build up on the rear quarter panel fascias
- The rear quarter panel of the vehicle is obstructed or partially obstructed by an adjacently parked vehicle or object
- Approaching vehicle passing at speeds greater than 24 km/h (15 mph)
- Severe weather conditions
- Driving in reverse (R) faster than 5 km/h (3 mph)
- Backing out of an angled parking spot
Due to the nature of radar technology, there may be certain instances when the CTA system alerts the operator, however no objects or vehicles are present when backing up. This is known as a false alert. False alert rate of up to 5% (5 times out of 100 reversals) is normal. Circumstances that may cause a false alert when backing up are backing out of a garage, backing into a parking space and objects or vehicles that are very close to the radar sensors. False alerts are temporary and self-correct.
NOTE: The CTA system customer ON/OFF feature is not available on early build hybrid vehicles.
The CTA system can be turned off by selecting the CTA system ON/OFF function in the message center. The CTA system is turned off in the IPC message center by selecting the CTA system with the SETUP switch for the message center and selecting the system on or off with the RESET switch. The message "CTA SYSTEM OFF" is displayed in the message center. The CTA system cannot be deactivated in the message center when the transaxle is in REVERSE (R). The system is reactivated on the next ignition cycle.
The CTA system can be disabled permanently (even after an ignition cycle) by using a scan tool. When using the scan tool disable function in the programmable parameters menu, the CTA system remains disabled until it is reactivated using the scan tool. When the system is disabled the IPC message center displays "CTA DISABLED". A system fault occurs if the CTA system is not disabled in both the SOD-L and the SOD-R.
There are some system faults that set DTCs which are logged in the SOD-L or SOD-R. These DTCs that are logged can set a message in the IPC message center that displays "CTA SYSTEM FAULT". There are also some symptom based faults that do not set a DTC. GO to Symptom Chart. Blind Spot Monitoring
Blocked Sensor
NOTE: The CTA system faults may not occur until the transaxle is placed in REVERSE (R).
An excessive build up of materials on the left and/or right rear quarter panel fascias, such as mud or snow, can cause the BLIS(TM) or CTA system functionality to degrade. Heavy rain can have the same effect. If the system is in a blocked state, the radar misses targets, but still counts them.
After approximately 4 counted/missed targets, the system sends a blocked sensor message over the Medium Speed Controller Area Network (MS-CAN) to the IPC. The IPC message center displays "BLIND SPOT NOT AVAILABLE" or "CTA NOT AVAILABLE" message. The not available message is followed by a "BLOCK SENSOR SEE MANUAL" message in the IPC message center. If the blocked condition is determined by either system the message center displays "BLIND SPOT NOT AVAILABLE" or "CROSS TRAFFIC NOT AVAILABLE" and the appropriate left and/or right exterior mirror BLIS(TM)/CTA LED illuminates.
The message center warning can be cleared by the driver but the exterior mirror BLIS(TM)/CTA LED remains illuminated. Once the blockage is removed, the system requires some drive time and a system detection of at least 2 vehicle objects prior to realizing it is unblocked. The ignition key can also be cycled off to clear the blocked state. However, if the blockage is still present after the key cycle and after some drive time, the system detects again that it is blocked. The blocked message is displayed again in the IPC message center.
Due to the nature of radar technology, it is possible to get a blockage warning and not actually be blocked. This is rare and known as a false blockage warning. A false blocked condition either self-clears or clears after an ignition cycle.
There are several conditions that cause the BLIS(TM) or CTA system to not operate correctly These conditions include:
- Ice, snow or soil adhering to the rear quarter panel surface around the radar sensor.
- Adverse weather conditions such as heavy rain or heavy snow or under conditions where water is sprayed.
The rear quarter panels and rear bumper cover should be cleaned of mud, snow, ice or any obstruction to restore normal operation.
Network Communication
While there are numerous messages internal to the SOD-L and SOD-R, the following messages are utilized by the BLIS(TM) and CTA system.
BLIS(TM) and CTA System Network Communication Messages
NOTE: Both the Medium Speed Controller Area Network (MS-CAN) and the High Speed Controller Area Network (HS-CAN) are used for intermeddle communication. A gateway message is transferred from one network to another network through the IPC. Refer to Information Bus for network communication information.
