Blocked Sensor

WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

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™ 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™ /CTA LED illuminates.

The message center warning can be cleared by the driver but the exterior mirror BLIS™ /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™ 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.