Vision system error

[Jayfdee]

I took my P4 for a flight and got Vision system error notification, right downward sensor fault.
I have been doing my best to troubleshoot, but I need some new ideas.
I have been trying to calibrate the sensors on the DJI assistant, the forward ones calibrate ok, but the downward ones are not detected. On the downward calibrate screen there is a small window on the left which shows the image from the cameras, and if I cover the left camera the small window goes dark, if I cover the right camera nothing happens, which leads to me to conclude that the RHS camera is indeed not working.
The firmware is up to date, the AC flies OK, I have never crashed or mishandled, where do I go next.
Should I remove the bottom cover plate and check seating of camera etc, any help or suggestions will be much appreciated.
For the record, I have tested with Litchi and with both IOS and android device and still the same fault.
I have of course cleaned the camera glass, it was not dirty anyway. Also refreshed the firmware.
Help

 

[Jayfdee]

OK, good news I fixed the problem and the P4 is now perfect.
So for the record, this is what |I did.
After many frustrating hours of attempting to calibrate the downward sensors, and refreshing and downgrading, and upgrading the firmware, and re installing DJI go,, I decided to beleive what was being reported on the app. Faulty RHS downward sensor.
I was lucky to come across someone breaking a P4 for spares, and acquired the vision module board, sold as working.
Fitting the board proved a struggle, largely because I am more at home heaving V8 engines in and out of my car, not brain surgery, my fingers are just too big.
Problems include scraping off all the white glue on the ribbon connectors, and trying to fit the board in one piece proved impossible for me, as you just cannot get your fingers in to the ribbon connectors.
I eventually dismantled the module, removed the 2 cameras, and the Ultrasonic module, and was then able to make the connections to the main board, and then mount the main module, and refit the cameras and Ultrasonics.
There is always great pleasure when you fire up the AC, and Lo and behold, all systems are go, apart from a calibration warning, so over to the DJI assistant again,15 mins of calibration, and job done.

It is of course possible that just remaking all the ribbon connectors fixed the problem, but "Whatever", I do not care, just glad to get airborne again.

Hope this helps anyone else with this problem.