Blind Spot Information Sys.(BLIS) - Function/Diag. Guide
RETAILER TECHNICAL JOURNAL 21232BLIS Functionally and Diagnostic Guide
Date: 7-27-2009
Reference: VIDA, TIE
Note!
If using a printed copy of this Retailer Technical Journal, first check for the latest online version.
This document is applicable to all Vehicles equipped with the Blind Spot Information System (BLIS).
BLIS is an information system that's designed to alert the driver of another vehicle possibly in the "blind spot". BLIS is intended mainly as a driver aid for dense traffic on multi-lane highway driving. When another vehicle enters the detection area, such as the BLIS equipped vehicle is passing or being passed by another, the driver will get a continuous light from one of the two indicators (LED's) while an object is being detected. The purpose of this indication is to alert the driver of the possibility of another vehicle in the detection area and for them to check prior to taking action.
System limitations:
- BLIS does not work in sharp curves.
- BLIS does not function when the vehicle is backing up
- If you are towing a wide trailer, this may prevent the BLIS cameras from detecting other vehicles in adjacent lanes.
- BLIS does not react to cyclists or mopeds.
- BLIS is designed to alert the driver of vehicles driving alongside going in the same direction.
- The BLIS cameras have the same limitations as the human eye. In other words, their "vision is impaired" by adverse weather conditions such as heavy snowfall/rain, dense fog, etc.
Functional description
Detection area
The picture below shows the critical area that may not be seen in the outer rear view mirrors which also is the area where BLIS, is designed to at minimum, detect other vehicles.
Day/Night mode
In daylight the system reacts to the shape of the surrounding vehicles. The system is designed to help detect motor vehicles such as cars, trucks, buses and motorcycles.
In darkness the system reacts to the headlamps of surrounding vehicles. If the headlamps of surrounding vehicles are not switched on then the system does not detect the vehicles. This means for example that the system does not react to a trailer without headlamps which is towed behind another vehicle
When is BLIS operational
The system is "default on" (set to be on each time the vehicle is started). At vehicle speeds of 6 mph (10 km/h) and above the system will indicate another vehicle in the blind spot.
The system is designed to indicate another vehicle in the blind spot if:
- you pass another vehicle at a speed of up to 6 mph (10 km/h) faster than the other vehicle.
- another vehicle passes you travelling up to 43 mph (70 km/h) faster than you are travelling.
It is possible to stop the BLIS indications to the driver by selecting the "BLIS OFF/ON button".
When BLIS "OFF" is selected the LED in the button goes out and a text message is shown on the Driver Information Module (DIM).
IMPORTANT NOTE: this only turns off the communication to the driver, the system is still be operating in the background.
If there is a need to reset the system you need to turn the engine off and restart.
Technical description
BLIS is a camera based system; the camera's take 25 pictures per second and compares them to a pre-determined algorithm (step-by-step problem-solving procedure) based on picture size/shape and delta (changes in) velocity.
False indications
The system detection algorithm is designed to read sharp contoured shapes that are in the detection area (cars, busses, trucks, motorcycles). Light reflections and shadows can trigger warnings since the camera can't always distinguish these from real objects. Advise the customer the system is operating as intended. Inform the customer why and how the continuous light from one of the two indicators (LED's) is present and that BLIS is an information system.
Here are some examples of situations where the BLIS indicator lamp may illuminate even if there is no other vehicle within the blind spot.
Reflections from shiny wet road surface or puddle.
Low sun shining into the camera.
Own shadow on large light smooth surface, e.g. noise barrier or concrete road surface.
Decreased system functionality / Messages in DIM
The BLIS system has a self diagnostic system to inform the driver about potential decreased system functionality. The diagnostic system software (SW) is included in the camera module units and the LH - RH cameras operate independently of each other. If either one of the camera's meet the criteria for decreased functionality the driver will be informed via flashing LED indicators and/or DIM message.
In addition to the "OFF/ON" indications there are three possible DIM messages to the driver:
1. BLIS Reduced function
This message informs the driver that the light conditions for either of the cameras is reduced and that the camera may not detect all objects due to low contrast conditions. The camera resets itself when the environment has returned to "normal". The "counters" in the diagnostic algorithms are reset to zero automatically when the light conditions are back to normal or an object with the headlamps on (night mode) is entering the BLIS detection area. The DIM message is removed automatically. Each of the cameras will continuously monitor the images and reset themselves when considered normal.
Examples of conditions that may give "Reduced function" message in DIM:
1. During dusk/dawn due to low light (most common cause of "reduced function").
2. Driving in complete darkness for longer than 10 minutes (safety reason since the cameras can not decide whether they are blocked or that there is no objects to detect).
3. Heavy rain or snow due to low light
4. Moisture on the Lens
5. Thin layer of dirt caused by dust, salt, etc
6. Strong light that saturates the image in a way that objects can not be recognized
What to do?
- Verify outside conditions noting amount of sunlight, weather, driving direction (North, South, East, West), time of day.
- Ensure the lens is clean: Clean with a soft cloth or a damp sponge. Clean the lenses carefully so that they are not scratched.
- Check the function of the lens defroster: The heater is active in temperatures below 82°F (28°C). You should be able to feel the heater with your finger; the area around the chrome ring/lens should be "warm to the touch", or use ice spray (PN 1161731) spray on the lens and see if the ice melts.
If the system does not reset, turn the engine off and restart.
AGAIN NOTE! The BLIS system will not be reset by selecting the OFF/ON button. This will only stop/start the LED indication to the driver. The system will still work under the same conditions in the background.
Inform the customer that the system is OK. The message is to inform the driver of the actual status of the system in the current driving conditions.
2. Camera blocked
When the camera has been reporting "Reduced function" in excess of 10 minutes without change the system shifts over to the "Camera Blocked" message in the DIM, and will be displayed together with a constant flashing from the BLIS LED's. This is the BLIS systems way to inform the driver that the BLIS system can't work under the current driving conditions.
Examples of conditions that may give Camera Blocked message in DIM
- During dawn / dusk - Low sun, it's dark on one side of the car and bright on the other.
- Heavy rain or snow - The camera gets blocked.
- Moisture on the Lens
What to do?
- Verify outside conditions noting amount of sunlight, weather, driving direction (North, South, East, West), time of day.
- Ensure the lens is clean - Clean with a soft cloth or a damp sponge. Clean the lenses carefully so that they are not scratched.
- Check the function of the lens defroster: The heater is active in temperatures below 82°F (28°C). You should be able to feel the heater with your finger; the area around the chrome ring/lens should be "warm to the touch", or use ice spray (PN 1161731) spray on the lens and see if the ice melts.
If the system does not reset, turn the engine off and restart.
AGAIN NOTE! The BLIS system will not be reset by selecting the OFF/ON button. This will only stop/start the LED indication to the driver. The system will still work under the same conditions in the background.
Inform the customer that the system is OK. The message is to inform the driver of the actual status of the system in the current driving conditions.
3. BLIS Service Required
"BLIS Service Required" message in the DIM informs the driver that there can be an internal failure within the system. i.e. communication internally within the camera, between the cameras and car communication system or a short circuit of one of the indicator LED's. This means that there is a risk that the camera may not correctly identify another vehicle in the detection area or being able to inform the driver.
What to do?
- Check the function of the lens defroster: The heater is active in temperatures below 82°F (28°C). You should be able to feel the heater with your finger; the area around the chrome ring/lens should be "warm to the touch", or use ice spray (PN 1161731) spray on the lens and see if the ice melts.
- Check for any relevant Retailer Technical Journals and follow the instructions
- Read out fault codes and consult the CSC symptom based fault tracing in VIDA; take appropriate action.
- Reset the system and see if the message returns, if the message returns; replace the mirror.