Park Assist System Temporarily Unavailab

[JERMB]

Well, checked again harness and sensors, all good, I think there is a problem with module. Can someone say, where is located module with this code: C43490?

[IMAY2023]

That looks like a foot sensor but it has nothing to do with parking sensors. It is located under the rear bumper. Parking sensors are connected directly to the CEM. on FL and EN connectors.

[JERMB]

Ok, let's dive into background: 

I have two XC90, one is MY2018 T5, another MY2017 T6. I had similar parking issues with T5, what I did, I opened PAM settings in diagnosis and was able to see which sensor is broken. Now with  T6 I even can not connect to the PAM module, diagnosis shows, that its unreachable. So. I am assuming,  that issue is somewhere around control unit. More over T6 had new OEM harness (replaced after accident).

[IMAY2023]

For both of your vehicles it parking assists is exactly the same. There is no separate HW (physical) PAM module, it is embedded in the CEM itself. 
Check out the below links for wiring and operations. 
MY2018 T5   MY2017 T6

Not sure which harness is replaced but it might have a short after or on the bumper to car harness connector.

[trokemp]

I had a similar problem. Due to a one fault sensor all parking assist system went down. I had these DTCS:

Code:

PAM-B1B3614 Right Front Outer Sensor. General Electrical Failures. Circuit short to ground or open.
PAM-B1B3814 Right Front Inner Sensor. General Electrical Failures. Circuit short to ground or open.
PAM-B1B4014 Left Front Outer Sensor. General Electrical Failures. Circuit short to ground or open.
PAM-B1B4214 Left Front Inner Sensor. General Electrical Failures. Circuit short to ground or open.

As I understand if any of these DTCs occurs, CEM disables the whole 12V supply to the sensors (checked this). Then I checked each sensor by multimeter if there is a short circuit between ground/+12V, ground/signal pin or signal pin/+12V. All were okay. After that I decided to use a 12V power supply and power each of sensors and one of them went hot after applying 12V. So I marked it as fault and replaced. Then cleared all DTCs and parking assist became available. I used the following diagram to test sensors:

[JERMB]

Ok, tried directly plug 12V/Ground and see what happens, unfortunately no one started heat or beep. Well, now I am thinking that sensors can be mixed between each other. Is it possible somehow to see parking sensors codes and places where it should be?

Currently my parking sensors with codes looks like this:

https://drive.google.com/file/d/1-6nepl9...sp=sharing

I do not find place where *011 sensors have to be located. Also I am not sure about front outer sensor location.

[trokemp]

I don't think the order of sensors is important. As far as I remember outer sensors (at wheel arch) have different shape (connector angle). If it fits, it should work.
Another way to test it is to measure the current consumption of each sensor. The bad one will have the highest current of them all. For example: good sensors will have current in range 80-100mA, the bad one 200mA. It's not the real values, just to illustrate how to differentiate them.

[ElectricEel]

Check the small battery. If battery bad then park assist won't work.

[IMAY2023]

Ok, tried directly plug 12V/Ground and see what happens, unfortunately no one started heat or beep. Well, now I am thinking that sensors can be mixed between each other. Is it possible somehow to see parking sensors codes and places where it should be?

Currently my parking sensors with codes looks like this:

https://drive.google.com/file/d/1-6nepl9...sp=sharing

I do not find place where *011 sensors have to be located. Also I am not sure about front outer sensor location.

This does not make sense. On My2019 S60 the rear parking sensors and front parking sensors have different connectors. Meaning it's not possible to fit the front parking sensor connector to the rear bumper harness and vice versa. How come you have same part numbers?

[JERMB]

Small battery is new, installed two month before. However, I give up and passed car to workshop. Will update what was the issue.

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Ok, tried directly plug 12V/Ground and see what happens, unfortunately no one started heat or beep. Well, now I am thinking that sensors can be mixed between each other. Is it possible somehow to see parking sensors codes and places where it should be?

Currently my parking sensors with codes looks like this:

https://drive.google.com/file/d/1-6nepl9...sp=sharing

I do not find place where *011 sensors have to be located. Also I am not sure about front outer sensor location.

This does not make sense. On My2019 S60 the rear parking sensors and front parking sensors have different connectors. Meaning it's not possible to fit the front parking sensor connector to the rear bumper harness and vice versa. How come you have same part numbers?

On XC90 there are same connectors for front and rear harness.