Park assist sensors

First I would check the sensor eye to see if you have a bit of dirt or mud over one of them. Here are diagrams to help you see how to replace the sensors.

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

Cheers

I would do them all, here is a guide to help you test.

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:

1. 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 Rear
Parking� Assist� Component� Views.
2. Turn� ON� the� ignition.
3. Place� foot� on� the� brake.
4. 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
Sensor� Supply� Voltage� Circuit� and� Sensor� Low X
Reference� Circuit Flashes� in� the� following� sequence:
Sensor� Supply� Voltage� Circuit� and� Sensor� Low
Reference� Circuit 1. Amber� Outside
8 X X X 2. Amber� Outside� and� Amber� Middle
IMPORTANT: 3. Amber� Middle� and� Red� Outside
This� diagnostic� pattern� sets� for� an� open� sensor 4. Red� Outside
supply� voltage� circuit� and� sensor� low
reference� circuit.
Sensor� Supply� Voltage� Circuit

9 IMPORTANT: X X X
This� diagnostic� pattern� sets� for� a� short� to
ground� in� the� sensor� supply� voltage� circuit.
DIAGNOSTIC� TROUBLE� CODE� (DTC)� CLEARING

The� rear� parking� assist� diagnostic� sequences� may� be� cleared� in� one� of� the� following� ways:

Vehicle� Moving

IMPORTANT: The� sequences� will� not� clear� if� the� rear� parking� assist� diagnostic� connector� is� grounded.

1. Drive� the� vehicle� forward� at� least� 24� km/h� (15� mph).
2. Stop� the� vehicle.
3. Turn� the� ignition� OFF.

Vehicle� Stopped

IMPORTANT: The� sequences� will� not� clear� if� the� rear� parking� assist� diagnostic� connector� is� grounded.

1. Turn� the� ignition� ON.
2. Place� your� foot� on� the� brake.
3. Shift� the� vehicle� into� REVERSE� within� 5� seconds.
4. Turn� the� ignition� OFF.
Good luck arrow points to grounding for dtc codes.