Headunit not powering on automaticaly

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Cole
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Headunit not powering on automaticaly

Post by Cole »

I bought Polo 9n3 recently and have a few issues with it.
The main thing that's bugging me is that the headunit isn't powering on when turning the key in lock. The HU is RCD 200.

I have tested a different HU, the result is the same, also I changed the ignition lock switch with no results.
Finally I pulled the HU and tested the remote line in the HU connector with a probe (one with a small bulb) and it doesn't light up regardless of the key position.
The thing I don't know is the remote line powered by 5V or 12V, I don't think the probe lights up on 5V?

Do you guys have any idea where to look next? The fuses are all OK.
I don't have any new ideas and no car electrician wants to try and figure it out (too much work for small payment).

Any suggestion is greatly appreciated!
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alexperkins
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Re: Headunit not powering on automaticaly

Post by alexperkins »

The RCD200 is a CAN controlled headunit. It is sent a wake up signal from the BCM inside the car rather than being sent a 12V ignition live.

Are you having any other problems with things not waking when the ignition is on?
Cole
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Re: Headunit not powering on automaticaly

Post by Cole »

Oh! OK, didn't know that, I found some picture on Google with a pin layout which looked like mine so I assumed...

I don't know if that's connected with it, but my signal indicator speaker (buzzer?) is silent, that's the second issue I have on the car.
Also, I don't get the warning "beep" when I hit reserve or start moving with handbrake on. If I'm not mistaken all of those should trigger a sound from the buzzer...
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alexperkins
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Re: Headunit not powering on automaticaly

Post by alexperkins »

Yes they should. That could be a fault on the buzzer in the cluster. It’s not uncommon on these

Have you got access to VCDS for diagnostics? That might help as the radio can be tested
Cole
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Re: Headunit not powering on automaticaly

Post by Cole »

Can I test the buzzer myself somehow? Something in a sense to remove the instrument cluster and connect it to a small battery without letting out the magic smoke? :shock:
If the buzzer is dead then I have no means of repairing it... :(

Regarding VCDS, a friend of mine works in a car repair shop and he borrowed for a day some kind of Bosch diagnostic tool but it didn't show any errors (the electrician that works with him didn't want to try to repair it).
I'll try and find someone who has VCDS to try and find errors...
I'm sorry if that's a stupid question but, are those "VAG CAN PRO - better than VCDS" on Aliexpress any good?

I suppose that there's no sense in swapping out the BCM for testing since it's vehicle specific?
Cole
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Re: Headunit not powering on automaticaly

Post by Cole »

I have found a guy who's willing to borrow me the cable and VCDS soft.

Where in VCDS should I look for the option to test the radio or the BCM?
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iichel
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Re: Headunit not powering on automaticaly

Post by iichel »

you could have a look at the measuring values or measuring blocks in the radio module (number 56) for an ignition signal.
Cole
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Re: Headunit not powering on automaticaly

Post by Cole »

I have connected the car to VCDS, there was a lot fewer options than I thought it would be...
Under the module 56-Radio I have found nothing and there was no "Long code helper" button, just a couple of options that can be changed in the code.

We found some sort of Fault code - 00849 - S-contact at Ignition/starter switch (D)
25-00 - Uknown Switch condition

I have googled the Fault code and on Ross Tech one of the possible solutions is "Check terminal S".
Does anybody know what that means, what or where is terminal S?

I hope that the wiring loom is not faulty... :shock:
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iichel
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Re: Headunit not powering on automaticaly

Post by iichel »

S contact is the solenoid that you hear click as you pull the key from the ignition lock.
Cole
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Re: Headunit not powering on automaticaly

Post by Cole »

Thank You for the fast reply.

Do You know where can I find this solenoid? I can't seem to find anything on Google regarding this error, except a topic on Ross-Tech forum which has no answer...

The ignition switch and the connector are OK, I have checked that...
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