HeadUnit Won't Switch To Reverse Mode

[SleAze]

Hey, I have an Audi A3 2012, equipped with a Wondefoo PX5 head unit aswell as a canbus decoder.
Before installing a reverse camera, everytime i switched to reverse it automatically went to "Reverse Mode" And AVIN.apk popped out (even though it was just stating "No signal" - because no camera was installed).

I have installed a reverse camera, gave it 12V and connected the RCA cable directly to the "CCD AVIN" input from the HeadUnit - without connecting the red power cable from the RCA cable to anything. (It recognised reverse automatically via the canbus i guess).

Everything worked great for I think 4 months, and this week without any notice, when i switched to reverse simply nothing happaned.
Since then the headunit simply won't automatically go to reverse mode.

Nothing was changed, so I have no clue what to do..
Someone who expirienced something like this? The CanBus decoder still works great except the reverse mode (as if it's unplugged the system won't start on because it doesn't get any signal that the ACC is on without the decoder).

This is the HeadUnit I have, with Android 8.0 4GB of RAM and 32GB internal memory: https://he.aliexpress.com/item/Andro...27424c4dT5D6nS

 

[samisnake]

hold down the left button, the power one, for around 10 seconds to force the system to reboot. does that make any difference?

 

[SleAze]

hold down the left button, the power one, for around 10 seconds to force the system to reboot. does that make any difference?

Unfortunatley no

 

[samisnake]

Possible your canbus adapter has a fault, and I think I've read somewhere that's it's possible for the reverse gear canbus signal to have errors.

Could try disconnecting the car battery for a while to reset it.

Where did you get the cameras 12v from

 

[SleAze]

Possible your canbus adapter has a fault, and I think I've read somewhere that's it's possible for the reverse gear canbus signal to have errors.

Could try disconnecting the car battery for a while to reset it.

Where did you get the cameras 12v from

I got 12V for the camera from the rear wiper (as the reverse signal doesn't give a stable 12V).
I tried disconnecting the canbus adapter and powering the headunit without it but it simply won't start (which means the canbus adapter works as it should I guess?).

I'll try disconnecting the battery tomorrow and see if that helps.

 

[samisnake]

Na it won't power on without the adapter. You'd have to run an acc power wire from the fuse box or cig lighter to do that. But that'd be pointless removing it as you'd lose steering wheel controls and the illumination, and the unit still won't recognise reverse.

Worst case scenario, you simply run a wire from the reverse light to the reverse wire on the loom.

Quick question, does the reverse light work? Ruling out a faulty reverse switch.

 

[SleAze]

Na it won't power on without the adapter. You'd have to run an acc power wire from the fuse box or cig lighter to do that. But that'd be pointless removing it as you'd lose steering wheel controls and the illumination, and the unit still won't recognise reverse.

Worst case scenario, you simply run a wire from the reverse light to the reverse wire on the loom.

Quick question, does the reverse light work? Ruling out a faulty reverse switch.

Yes it does work. In addition I can still hear the "Beep" from the parking sensors turning on (factory fitted), and of course the parking sensors themselves work when i'm in reverse.

 

[SleAze]

Na it won't power on without the adapter. You'd have to run an acc power wire from the fuse box or cig lighter to do that. But that'd be pointless removing it as you'd lose steering wheel controls and the illumination, and the unit still won't recognise reverse.

Worst case scenario, you simply run a wire from the reverse light to the reverse wire on the loom.

Quick question, does the reverse light work? Ruling out a faulty reverse switch.

I just tried disconnecting the battery for 5 mins, it didn’t help - headunit still doesn’t go into reverse automatically as it used to do..

What could be the problem?

 

[samisnake]

Either the canbus adapter for the headunit is faulty, which can happen, or there's some reason that the canbus system of the car isn't giving the reverse signal.

At this point I would test to make sure the unit still goes into camera mode when 12v is applied to the reverse wire on the unit, and plug into vcds or similar to see if there are any fault codes/dtc.

 

[SleAze]

Either the canbus adapter for the headunit is faulty, which can happen, or there's some reason that the canbus system of the car isn't giving the reverse signal.

At this point I would test to make sure the unit still goes into camera mode when 12v is applied to the reverse wire on the unit, and plug into vcds or similar to see if there are any fault codes/dtc.

VCDS scan shows no errors at all, can it be that the canbus adapter is faulty but all of the other functions work 100% fine? (steering wheel controls, powering on when the ACC is switched ON, etc..)

So you basically say my last option is to try and wire it up with the reverse signal feed (as if I don't have a canbus adapter, and see if that works?)

 

[samisnake]

I've seen that mentioned on xda developers forum, where things like illumination or steering controls or reverse don't work individually but everything else does.
Then they've received a new adapter and it all works again, so it is possible.

Yeah if you exhaust all other options you can just wire it to the reverse light wiring. What I meant by testing it is to simply connect any 12v wire to the loose reverse wire on the headunit, as that'll have the same effect. If it works you know the headunit itself is fine

 

[SleAze]

I've seen that mentioned on xda developers forum, where things like illumination or steering controls or reverse don't work individually but everything else does.
Then they've received a new adapter and it all works again, so it is possible.

Yeah if you exhaust all other options you can just wire it to the reverse light wiring. What I meant by testing it is to simply connect any 12v wire to the loose reverse wire on the headunit, as that'll have the same effect. If it works you know the headunit itself is fine

Hey, sorry for the bump wanted to update: new canbus receiver arrived in the post office, switched them out - no luck. Still nothing in the head unit when I put reverse gear in.

I’m kinda lost and don’t know how to solve this issue.. I feel like it’s a software issue / a setting that has changed which I don’t know about.

The seller of the head unit is no use as the language gap is too big and he doesn’t understand me even though I simplified the issue.

I tried resetting the head unit and again no luck. Has anyone else had an issue like this?

 

[ab1702]

Hey, sorry for the bump wanted to update: new canbus receiver arrived in the post office, switched them out - no luck. Still nothing in the head unit when I put reverse gear in.

I’m kinda lost and don’t know how to solve this issue.. I feel like it’s a software issue / a setting that has changed which I don’t know about.

The seller of the head unit is no use as the language gap is too big and he doesn’t understand me even though I simplified the issue.

I tried resetting the head unit and again no luck. Has anyone else had an issue like this?

Have you changed any of the settings in the unit or installed a new rom or mcu? There’s a reverse option in car settings on the unit and also a reverse setting in the factory settings under other which can be changed. It sounds to me like one of these has been changed somehow. I don’t have a reverse camera so I turned mine off to purposely stop it from happening and it sounds like this has happened to you

 

[SleAze]

Have you changed any of the settings in the unit or installed a new rom or mcu? There’s a reverse option in car settings on the unit and also a reverse setting in the factory settings under other which can be changed. It sounds to me like one of these has been changed somehow. I don’t have a reverse camera so I turned mine off to purposely stop it from happening and it sounds like this has happened to you

Yeah it totally feels like a setting That has changed but unfortunately I can’t find anything weird / different. I only found 1 setting related to the reverse camera and it’s the same as always

 

[ab1702]

Yeah it totally feels like a setting That has changed but unfortunately I can’t find anything weird / different. I only found 1 setting related to the reverse camera and it’s the same as always

Where was that setting that you found?
Have you looked in factory settings like I said? In there you go to ‘other’ and then there is an option that says something like reverse prohibit.