Parking sensor not working

Are there vehicles in front of you when this happens? Some vehicles are fitted with a 'Lane Departure' system that warns you if your too close as you pass a parked car or high kerb. Waiting in traffic can also sometimes trigger this warning beep. This feature uses the same sensors as your front parking system. Some vehicles will allow you to turn this off if you go into the vehicles settings.
I think on the Outlander pressing and holding the "ASC OFF" button down for 3 to 5 seconds turns this off. Do the same thing again to turn it back on. Try it and see if it stops the beep the next time you are out in traffic.

What is it chiming ? Chimes for different reasons , headlamps on , seat belt not buckled , etc.... What warning light is lit on the instrument cluster ? if any . seat belt , air bag's etc...

Audible Warnings Description and Operation
The audible warnings alert the driver of a system concern or a critical vehicle condition. The following lists the audible warning priority and the pulse rate:
Fast rate chime (200 pulses per minute)
Medium rate chime (150 pulses per minute)
Slow rate chime (50 pulses per minute)
Single chime
Fasten Safety Belt Warning
The inflatable restraint sensing and diagnostic module (SDM) activates the fasten safety belt audible warning for 5-8 seconds. The fasten safety belt warning sounds and the fasten seat belt indicator illuminates when the following occurs:
• The ignition switch is in RUN, BULB TEST, or START position.
• The SDM detects that the driver's seat belt is not buckled (signal is low).
If the seat belt is buckled before the ignition is in RUN, BULB TEST, or START position, the chime does not sound. If the seat belt is buckled while the chime is sounding, the chime stops.
Key-In-Ignition Warning
The instrument panel cluster (IPC) activates the key-in-ignition audible warning. The key-in-ignition warning sounds when the following occurs:
• The ignition switch is in OFF, LOCK, or ACCY position.
• The body control module (BCM) determines that the driver's door is open (signal is low).
• The BCM determines that the key-in-ignition switch is closed (signal is low).
Lights On Warning
The instrument panel cluster (IPC) activates the lights on audible warning. The lights on warning sounds when the following occurs:
• The key is not in the ignition.
• The body control module (BCM) determines that the drivers door is open (signal is low).
• The BCM determines that the headlamp switch is in the park or head position.
Rear Parking Assist
The rear object sensor control module activates the audible warning. The audible warning sounds whenever any of the indicators are illuminated on the rear parking assist display. For a description of the rear parking assist system refer to Object Detection Description and Operation.
Turn Signal Reminder
The instrument panel cluster (IPC) sounds the turn signal reminder once per each flash of the turn signal lamps when:
• The ignition switch is in the RUN position.
• The turn signal switch is in either turn position, sensing, within 1 second, an open to B+ transition in the turn signal control circuit (left or right turn).
• The vehicle has traveled a distance of 1.2 km (0.75 mi) by counting pulses on the vehicle speed input circuit.
The IPC turns off the turn signal reminder when either the ignition switch is turned to the LOCK position or to the OFF position, or the turn signal switch returns to the OFF position, sensing, within 1 second, no transitions from open to B+ in either of the turn signal control circuits (left turn or right turn).
Additional Chimes
The following chimes will turn on when an associated indicator turns on in the instrument panel cluster (IPC):
• Low Fuel Indicator
• Low Oil Pressure Indicator
• OVER SPEED indicator
For a description of an indicator refer to Indicator/Warning Message Description and Operation.
For diagnosis of an indicator refer to Symptoms - Instrument Panel, Gages and Console.

Your have a problem with one of these systems , your best bet , take it to a qualified repair shop. They would do diagnostic's to find the problem .

Do any indicators illuminate when the chime sounds?
Go to Symptoms - Instrument Panel, Gages and Console
Go to Step 3
3
Turn the ignition OFF.
Remove the key from the ignition.
Turn the headlamp switch to OFF.
Close all of the vehicle doors.
Open one or more of the vehicle doors
Does the chime sound at all times regardless if the doors are open or closed?
Go to Step 15
Go to Step 4
4
Close all of the vehicle doors.
With a scan tool, observe the LF Door Ajar Switch parameter and the RF Door Ajar Switch parameter in the instrument panel cluster BCM/Inputs data list.
Do all of the Door Ajar Switch parameters display Door Closed?

With a scan tool, observe the Left Rear Door Ajar Sw. parameter and the Right Rear Door Sw. parameter in the instrument panel cluster BCM/Inputs data list.
Do all of the Rear Door Switch parameters display Closed?

This is a 21 step diagnostic trouble shooting flow chart .

The ultrasonic rear parking assist (URPA)
The URPA is equipped with a switch located above the driver information center (DIC) that can be used to disable the system.Do you have it disabled ?
Diagnostic Trouble Code (DTC) Displaying
This vehicle is equipped with an on-board diagnostic display feature capable of displaying diagnostic trouble codes using the 3 indicators on the rear parking assist display. After the bulb check has been completed, the red outside indicator flashes to indicate a malfunction with the system. The module disables operation of the URPA system under this condition.
In order to enter the diagnostic mode, complete the following actions:
With the ignition turned OFF, short the rear parking assist diagnostic connector to ground while the vehicle is in PARK. For the location of the rear parking assist (RPA) diagnostic connector, refer to Object Detection Component Views . It's under the front of the center console , by the BCM - body control module.
Turn ON the ignition.
Place foot on the brake.
Shift the vehicle into REVERSE within 5 seconds.
If the vehicle is not shifted into reverse within 5 seconds after turning the ignition ON, the diagnostic mode will still be initiated. However, a reverse input wiring fault will be registered as sequence #7 as shown in the Diagnostic Indicator table below. Refer to Diagnostic Trouble Code (DTC) Clearing for the specific steps on how to clear diagnostic trouble codes. After the reverse input wiring code is cleared, repeat the diagnostic trouble code displaying steps in order to enter the diagnostic mode.
When the diagnostic mode is first entered, the rear parking assist display displays the amber outside indicator and the red outside indicator. Then, the indicators on the rear parking assist display will display one or more of the sequences in the table below to indicate where the fault exists within the rear parking assist system. Refer to Diagnostic Trouble Code (DTC) Clearing for the specific steps on how to clear diagnostic trouble codes.

Diagnostic Indicators #
State/Fault Location
Amber Outside
Amber Middle
Red Outside
Flashing
1
Start of Diagnostics
X
--
X
--
2
RR Corner Object Sensor and Wiring
X
--
--
--
3
RR Middle Object Sensor and Wiring
X
X
--
--
4
LR Middle Object Sensor and Wiring
--
X
X
--
5
LR Corner Object Sensor and Wiring
--
--
X
--
6
Chime Warning Wiring
--
X
--
--
7
Reverse Input Wiring
--
X
--
X
8
Important: This diagnostic pattern sets for an open sensor supply voltage circuit and sensor low reference circuit.
Sensor Supply Voltage Circuit and Sensor Low Reference Circuit
X
X
X
X
Flashes in the following sequence:
Amber Outside
Amber Outside and Amber Middle
Amber Middle and Red Outside
Red Outside
9
Important: This diagnostic pattern sets for a short to ground in the sensor supply voltage circuit.
Sensor Supply Voltage Circuit
X
X
X
--

{: ) The PARK ASSIST OFF message will be displayed when the parking assist system is disabled due to conditions that disable or inhibit the system. The object alarm module requests the DIC display PARK ASSIST OFF when it detects one of the following conditions:
• The parking assist system is manually disabled using the driver information center (DIC). • An object is attached to the rear of the vehicle, such as a trailer, bicycle rack, trailer hitch receiver, or tow bar. • The object alarm sensors are covered by snow, mud, dirt, slush, or ice. • The vehicle bumper is damaged. • Excessive paint thickness on a replacement object alarm sensor. • The object alarm sensors are disrupted by vibrations, like those caused by a large nearby vehicle or from heavy equipment such as a jackhammer.
The SERVICE PARK ASSIST message will be displayed when the object alarm module detects a malfunction in the parking assist system and the system is disabled. It could be one of your sensors is at fault or even the module.

Have the RSS module checked for DTC'S - diagnostic trouble code's . That should always be the first step . An it is
Reverse sensing system Parking Aid The parking aid system consists of the:

• parking aid sensors
• parking aid speaker
• parking aid module

The parking aid system is activated when the parking aid module receives a network messages from the instrument cluster indicating that the vehicle is in reverse. The parking aid system sounds a warning to alert the driver of stationary objects near the rear bumper when REVERSE is selected. The parking aid system assists the driver in detecting certain objects while the vehicle moves in reverse at speeds less than 4.8 km/h (3 mph). The parking aid system may not detect angular or moving objects.

1. Visual Inspection Chart Electrical
   • Smart junction box (SJB) fuse 18 (10A)
   • Circuitry
   • Connector(s)
   • Parking aid sensors
   • Parking aid speaker
   • Parking aid module

Do you know what DTC'S are .

Parking Aid Module Diagnostic Trouble Code (DTC) Index DTC Description Source Action B1299 Power Supply Sensor Circuit Short to Ground Parking Aid Module Go To Pinpoint Test C . B1342 ECU is Faulted Parking Aid Module CLEAR the DTCs. REPEAT the parking aid module self-test. If DTC B1342 is retrieved again, INSTALL a new parking aid module. REFER to Parking Aid Module in this section. CLEAR all DTCs. REPEAT the self-test. B2477 Module Configuration Failure Parking Aid Module REFER to Section 418-01 . C1699 Left Rear Sensor Circuit Short to Battery Parking Aid Module Go To Pinpoint Test D . C1700 Left Rear Sensor Circuit Failure or Blockage Parking Aid Module Go To Pinpoint Test C . C1701 Left Rear Sensor Circuit Fault Parking Aid Module Go To Pinpoint Test E . C1702 Right Rear Sensor Circuit Short to Battery Parking Aid Module Go To Pinpoint Test D . C1703 Right Rear Sensor Circuit Failure or Blockage Parking Aid Module Go To Pinpoint Test C . C1704 Right Rear Sensor Circuit Fault Parking Aid Module Go To Pinpoint Test E . C1705 Left Rear Center Sensor Circuit Short to Battery Parking Aid Module Go To Pinpoint Test D . C1706 Left Rear Center Sensor Circuit Failure Parking Aid Module Go To Pinpoint Test D . C1707 Left Rear Center Sensor Circuit Fault Parking Aid Module Go To Pinpoint Test E . C1708 Right Rear Center Sensor Circuit Short to Battery Parking Aid Module Go To Pinpoint Test D . C1709 Right Rear Center Sensor Circuit Failure Parking Aid Module Go To Pinpoint Test C . C1710 Right Rear Center Sensor Circuit Fault Parking Aid Module Go To Pinpoint Test E . C1742 Rear Sounder Circuit Failure Parking Aid Module Go To Pinpoint Test F . C1743 Rear Sounder Circuit Short to Battery Parking Aid Module Go To Pinpoint Test F . Your best bet , take it to a qualified repair shop . Ford

{: ) The driver information center (DIC) displays SERVICE PARK ASSIST when the object alarm module detects a malfunction in the parking assist system and the system is disabled. The DIC also displays SERVICE PARK ASSIST when a loss of communication occurs with the object alarm module. Usually this is caused by faulty components or wirings. Better visit your dealer if still under warranty, for one park assist sensor only costs too much. If your bumper had been knocked off or had previous repairs outside the dealership, that's another thing.
The PARK ASSIST OFF message is displayed in the DIC when the parking assist system is disabled due to conditions that disable or inhibit the system. The object alarm module requests the DIC display PARK ASSIST OFF when it detects one of the following conditions:
• The parking assist system is manually disabled using the driver information center (DIC). • An object is attached to the rear of the vehicle, such as a trailer, bicycle rack, trailer hitch receiver, or tow bar. • The object alarm sensors are covered by snow, mud, dirt, slush, or ice. • The vehicle bumper is damaged, • Excessive paint thickness on a replacement object alarm sensor. • The object alarm sensors are disrupted by vibrations, like those caused by a large nearby vehicle or from heavy equipment such as a jackhammer.

{: ) SERVICE PARK ASSIST The driver information center (DIC) displays SERVICE PARK ASSIST when the park assist module detects a malfunction in the object detection system and sends a request to the DIC for display of the message. The DIC also displays SERVICE PARK ASSIST when there is a loss of communication with the park assist module.
PARK ASSIST OFF The PARK ASSIST OFF message is displayed in the DIC when the park assist system is disabled due to conditions that disable or inhibit the system. The red LED in the rear display, as well as, the telltale in the switch will be lit, notifying the driver the PARK ASSIST system is disabled. The object alarm module requests the DIC via the serial data circuit to display PARK ASSIST OFF when it detects that one of the following conditions is true:
• The object alarm system is disabled through DIC vehicle customization feature. Refer to the Owners Manual for more information. • An object is attached to the rear of the vehicle, such as a trailer, bicycle rack, or hitch receiver. • An object is hanging out of the endgate. • The park brake is not fully released. • The system receives vibrations from a large nearby vehicle or from a heavy equipment such as a jackhammer. In the case of objects attached to the rear of the vehicle such as a trailer, hitch receiver, or a bicycle rack, or objects hanging out of the endgate, the rear parking assist (RPA) will have an Automatic Object induced disable feature where the RPA will determine if the rear object is moving with the vehicle. If the RPA detects such a condition, the park assist will be disabled. The PARK ASSIST OFF message will continue to be displayed until the trailer hitch receiver is removed and the vehicle is driven forward above 24 km/h (15 mph).

Check the system for DTC'S - diagnostic trouble codes should be the first step in the diagnostic process . Then reading factory service repair manual how the system works , viewing wiring diagrams .
Object Detection Description and Operation
Ultrasonic Rear Park Assist Operation
The ultrasonic rear park assist system senses how close the vehicle is to an object. The distance is determined by the 4 object sensors located in the rear bumper. The object detection system will notify the driver when backing up at speeds less than 8 km/h (5 mph). The object detection system will use the rear parking assist (RPA) display and the radio speakers for notification.
When the ignition is ON and the vehicle is placed into reverse, the object detection system performs a bulb check. During the bulb check, the 3 indicators on the RPA will illuminate for approximately 2 seconds to indicate that the system is working. The object detection system performs a bulb check and operates when the following conditions are present:
• The ignition is ON.
• The vehicle is placed in REVERSE (R) for rear parking aid.
• The vehicle speed is less than 8 km/h (5 mph). At speeds greater than 8 km/h (5 mph), the object detection system is disabled. The red indicator flashes to warn the driver that the object detection system is disabled.
The object detection system senses how close the vehicle is to an object. The distance is determined by the 4 object sensors located on the rear bumper. When the system detects an object, one of the following will occur:
• If the object is less than 0.3 m (11 in) away from the vehicle, the amber outside, amber middle, and the red outside indicators flash and the chime sounds continuously for 3 seconds.
• If the object is less than 0.3-0.5 m (11-20 in) away from the vehicle, the amber outside, amber middle, and the red outside indicators are ON.
• If the object is 0.5-1.0 m (20-40 in) away from the vehicle, the amber outside, and the amber middle indicators are ON.
• If the object is 1-2.3 m (40-91 in) away from the vehicle, the amber outside indicator is ON with a single chime when the object is first detected.
Object detection system can detect objects 7.6 cm (3 in) wide and at least 25.4 cm (10 in) tall. It cannot detect objects above the level of the roof.
If the object detection system detects a malfunction, a diagnostic trouble code (DTC) will be stored and the object detection system will send a serial data communication message to the instrument panel (I/P) to SERVICE PARK ASSIST message on the driver information center (DIC). Then the chime will sound and the red indicator on the information telltale center will be lit continuously. The red LED in the rear display will be lit, notifying the driver that a malfunction exists. Message will clear once the driver acknowledges it.
Each object sensor is a three wire sensor that is both a transmitter and a receiver that comprises a signal circuit, a low reference circuit, and an 8-volt supply voltage circuit. The rear object control module supplies 8 volts to the object sensors via the object sensor supply voltage circuit and provides ground via the low reference circuit. The rear object control module triggers the sensors in a sequential loop and after each sensor transmits, the rear object control module uses the echo or signal return to calculate the distance and position of an object from the rear bumper. The rear object control module directly controls the RPA display.

Do you know what DTC'S are ?
DTC B0958 01: Parking Aid Rear Sensor 1 Left Corner Circuit Short to Battery
DTC B0958 06: Parking Aid Rear Sensor 1 Left Corner Circuit Short to Ground or Open
DTC B0958 08: Parking Aid Rear Sensor 1 Left Corner Circuit Signal Invalid
DTC B0958 21: Parking Aid Rear Sensor 1 Left Corner Circuit Incorrect Period
DTC B0959 01: Parking Aid Rear Sensor 1 Left Middle Circuit Short to Battery
DTC B0959 06: Parking Aid Rear Sensor 1 Left Middle Circuit Short to Ground or Open
DTC B0959 08: Parking Aid Rear Sensor 1 Left Middle Circuit Signal Invalid
DTC B0959 21: Parking Aid Rear Sensor 1 Left Middle Circuit Incorrect Period

DTC B0967 02: Parking Aid Switch Circuit Short to Ground
DTC B0968 00: Parking Aid Indicator Circuit


Your best bet , take it to a qualified repair shop.

have someone walk behind you when in reverse gear, it bleeps once to tell you its working then only beeps when close to an obstacle.

Check the connection to the vehicle speed sensor. You can check the vehicle speed sensor by using a voltmeter set at millivolt. Then pass a metallic object close to it. The sensor should induce voltage as you pass the metallic object close to it. If not replace the vehicle speed sensor.