BLIS ® and Cross Traffic Alert (CTA)

WARNING: This page is about a different car, the 2015 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

System Diagram

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Network Message Chart

IPC Network Input Messages

Broadcast Message	Originating Module	Message Purpose
Side obstacle sensor status - left	SODL	Used to communicate the operating status of the SODL and to command the BLIS ®/Cross Traffic Alert (CTA) message center displays.
Side obstacle sensor status - right	SODR	Used to communicate the operating status of the SODR and to command the BLIS ®/Cross Traffic Alert (CTA) message center displays.
Cross traffic alert left status	SODL	Used to command the Cross Traffic Alert (CTA) audio chime and the BLIS ® RTT.
Cross traffic alert right status	SODR

ACM Network Input Messages

Broadcast Message	Originating Module	Message Purpose
Chime mode	IPC	Used to command the Cross Traffic Alert (CTA) audio chimes on without touchscreen.

DSP Network Input Messages

Broadcast Message	Originating Module	Message Purpose
Chime mode	IPC	Used to command the Cross Traffic Alert (CTA) audio chimes on vehicles with touchscreen.

DDM Network Input Messages

Broadcast Message	Originating Module	Message Purpose
BLIS ®/Cross Traffic Alert (CTA) LED command - left	SODL	Used to command the LH BLIS ®/Cross Traffic Alert (CTA) LED on and off.

PDM Network Input Messages

Broadcast Message	Originating Module	Message Purpose
BLIS ®/Cross Traffic Alert (CTA) LED command - right	SODR	Used to command the RH BLIS ®/Cross Traffic Alert (CTA) LED on and off.

SODL Network Input Messages

Broadcast Message	Originating Module	Message Purpose
BLIS ®/Cross Traffic Alert (CTA) enable/disable command	IPC	Used to enable/disable the BLIS ® or Cross Traffic Alert (CTA) based on driver input.
Ignition key type	BCM	Used to disable the ability to turn OFF the BLIS ® and Cross Traffic Alert (CTA) when a MyKey ® restricted key is in use.
Gear lever position	PCM	Used to turn the BLIS ® and Cross Traffic Alert (CTA) system on and off depending the gear lever position.
Vehicle speed	PCM	Used to activate the BLIS ® after an ignition cycle and deactivate the Cross Traffic Alert (CTA) system when the vehicle speed exceeds preset thresholds.
Wiper status	SCCM	Used to determine ambient weather conditions for correct system operation.
Turn signal status	SCCM	Used to generate the secondary alert when a turn signal is activated.
BLIS ® driver LED status	DDM	Used to confirm the operating status of the LH exterior mirror BLIS ® LED.
Active park assist system status	PAM	Disables the Cross Traffic Alert (CTA) warnings during active park assist maneuvers.
Trailer lamp connected	TRM	Disables the BLIS ® and Cross Traffic Alert (CTA) when a trailer is electrically connected to the vehicle.
VIN information	BCM	Contains VIN information.

SODR Network Input Messages

Broadcast Message	Originating Module	Message Purpose
BLIS ®/Cross Traffic Alert (CTA) enable/disable command	IPC	Used to enable/disable the BLIS ® or Cross Traffic Alert (CTA) based on driver input.
Ignition key type	BCM	Used to disable the ability to turn OFF the BLIS ® and Cross Traffic Alert (CTA) when a MyKey ® restricted key is in use.
Gear lever position	PCM	Used to turn the BLIS ® and Cross Traffic Alert (CTA) system on and off depending the gear lever position.
Vehicle speed	PCM	Used to activate the BLIS ® after an ignition cycle and deactivate the Cross Traffic Alert (CTA) system when the vehicle speed exceeds preset thresholds.
Wiper status	SCCM	Used to determine ambient weather conditions for correct system operation.
Turn signal status	SCCM	Used to generate the secondary alert when a turn signal is activated.
BLIS ® passenger LED status	PDM	Used to confirm the operating status of the RH exterior mirror BLIS ®) LED.
Active park assist system status	PAM	Disables the Cross Traffic Alert (CTA) warnings during active park assist maneuvers.
Trailer lamp connected	TRM	Disables the BLIS ® and Cross Traffic Alert (CTA) when a trailer is electrically connected to the vehicle.
VIN information	BCM	Contains VIN information.

BLIS ®

NOTE: On vehicles equipped with factory trailer tow, if a trailer is electrically connected to the vehicle, the BLIS ® is disabled.

NOTE: On vehicles without factory trailer tow, if a trailer is connected to the vehicle, the BLIS ® system may detect the trailer and cause a false alert.

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 ®/Cross Traffic Alert (CTA) LED 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 ®/Cross Traffic Alert (CTA) LED flashes rapidly. When the turn signal is off, the BLIS ® target warnings are a constant LED illumination.

NOTE: The BLIS ® is not intended to detect parked vehicles, pedestrians, or objects such as fences, guard rails or trees.

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.

Cross Traffic Alert (CTA) System

NOTE: The Cross Traffic Alert (CTA) system is only active when reverse gear is selected.

NOTE: On vehicles equipped with factory trailer tow, if a trailer is electrically connected to the vehicle, the Cross Traffic Alert (CTA) is disabled.

NOTE: On vehicles without factory trailer tow, if a trailer is connected to the vehicle, the Cross Traffic Alert (CTA) system may detect the trailer and cause a false alert.

When the transmission is in reverse, the Cross Traffic Alert (CTA) system can detect a vehicle or a bicycle that is approaching at a speed between 8 km/h and 64 km/h (5 mph and 40 mph) and time to impact is between 1 and 2.5 seconds. The distance at which an alert is generated varies depending on the speed of the approaching vehicles or bicycles. The Cross Traffic Alert (CTA) system response time and performance can degrade if vehicles are approaching at speeds greater than 64 km/h (40 mph).

An adjacent parked vehicle or object can affect the systems ability to detect approaching vehicles or bicycles (refer to figure 1 below). Parking at extreme angles can further affect the systems ability to detect approaching vehicles or bicycles (refer to figure 2 below).

Backing towards a curve road can also affect systems ability to detect approaching vehicles or bicycles (refer to figure 3 below).

Cross Traffic Alert (CTA) detection zones:

Courtesy of FORD MOTOR COMPANY

Courtesy of FORD MOTOR COMPANY

Courtesy of FORD MOTOR COMPANY

The Cross Traffic Alert (CTA) system is designed to detect any objects approaching the vehicle at a speed equal to or greater than 8 km/h (5 mph). This includes vehicles and bicycles. The Cross Traffic Alert (CTA) system has some detection limitations due to the nature of the radar technology used by the SODL and SODR. The system cannot normally detect stationary vehicles, humans, animals or objects such as fences, guard rails or trees.

Circumstances that may cause non-detection are:

Debris build-up or damage to the rear lamp assemblies
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 64 km/h (40 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 Cross Traffic Alert (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 damage to the rear lamp assemblies
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 Cross Traffic Alert (CTA) system is active and an object is detected by the SODL or SODR, the BLIS ®/Cross Traffic Alert (CTA) LED 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 ®/Cross Traffic Alert (CTA) LED based on messages received from the SODL and SODR.

Each time the vehicle is started, the SODL and SODR command the DDM and PDM to illuminate the exterior mirror BLIS ®/Cross Traffic Alert (CTA) Light Emitting Diodes (LEDs) for approximately 3 seconds, indicating the BLIS ® and Cross Traffic Alert (CTA) system is operational.

If a BLIS ® or Cross Traffic Alert (CTA) system fault is present, the exterior mirror BLIS ®/Cross Traffic Alert (CTA) Light Emitting Diodes (LEDs) remains off, the IPC BLIS ® RTT illuminates and a message center warning displays BLIND SPOT SYSTEM FAULT.

BLIS ® and Cross Traffic Alert (CTA) Message Center Function

NOTE: Cross Traffic Alert (CTA) system faults may not be detected until the transmission is placed in reverse.

NOTE: The BLIS ® and Cross Traffic Alert (CTA) system menus in the message center are not available when a MyKey ® restricted key is in use.

BLIS ® can be turned off by using the blind spot on/off function in the message center. When the BLIS ® has been turned off by the driver or if a system fault is present, the BLIS ® RTT in the message center remains on. When turning the system on or off, the exterior mirror Light Emitting Diodes (LEDs) flash 2 times. When the BLIS ® is turned off, the driver cannot receive any alerts. The system remains off until turned back on by the driver.

The Cross Traffic Alert (CTA) system can be turned off by selecting the Cross Traffic Alert (CTA) system on/off function in the message center. The system defaults to on with each ignition cycle.

There are some system faults that set Diagnostic Trouble Codes (DTCs) in the SODL, SODR, DDM or PDM. These Diagnostic Trouble Codes (DTCs) can set a message in the IPC message center that displays BLIND SPOT SYSTEM FAULT and/or CROSS TRAFFIC SYSTEM FAULT. There are also symptom based faults that do not set a DTC.

Blocked Sensor

NOTE: Blockage sensing becomes active after the wipers are activated.

NOTE: A blocked state is not a system fault. A blocked state is a normal mode of operation under blocked conditions.

An excessive build-up of materials on the rear lamp assemblies, such as mud or snow, can cause the BLIS ® or Cross Traffic Alert (CTA) system functionality to degrade. Heavy rain can have the same affect on the system. If a blocked state is detected, the SODL and SODR blockage sensing senses the performance degradation and enters the SODL and SODR into a blocked state. The performance degradation means alerting late on targets or additional missed targets. Upon entering a blocked state, the SODL and/or SODR send a status message over the MS-CAN to the GWM. The GWM then sends the status message to the IPC on the HS-CAN3. The message center displays BLIND SPOT NOT AVAILABLE SENSOR BLOCKED or CROSS TRAFFIC NOT AVAILABLE SENSOR BLOCKED and the LH and RH exterior mirror BLIS ®/ Cross Traffic Alert (CTA) Light Emitting Diodes (LEDs) illuminate.

The message center warning can be cleared by the driver, but the amber BLIS ® off RTT in the IPC remains illuminated. A blocked state will self-clear when blockage sensing senses performance has returned to normal operation. The ignition can also be cycled off to clear the blocked state. If the blockage is still present after the ignition cycle, or after some drive time the system detects again that it is blocked, the blocked sensor message is displayed again in the message center and the amber BLIS ® off IPC RTT is illuminated again.

Due to the nature of radar technology, it is possible to get a blocked sensor warning without the radar sensor being blocked. This is rare and is known as a false blockage warning. A false blocked condition either self-clears or clears after an ignition cycle.