SC-901 stereo stops playing

jkasdorp · Post by **jkasdorp** » 21 Mar 2012, 10:28

Hello,
I recently bought a '98 V70 R
Now my stereo stopped playing while listening to the radio. All the radio controls freezed and the display showed all the time the same RDS information, even after switching the unit off and on. The cd player seemed to be working, but I had no cd's in the car so I'm not sure it was actually working. When the ignition was switched off and on again the stereo didn't power up at all . I checked the fuse, it was ok. Now the stereo is asking for the code wich I don't have. Tomorow I will go to a dealer and try to obtain the code. But in the mean time I'd like to know if this is a common problem, is there a way to reset the stereo, or is it broken now?
The Stereo is a SC-900 with dolby pro-logic and center speaker.
Any input will be appreciated.

Regards,

Gerben

Post by **fazool** » 21 Mar 2012, 14:21

Since you still saw information on the display of the stereo head unit, you did not lose external power to the unit (unless it was very briefy and came right back). Because you need a new code to unlock it, it sounds like the stereo head unit lost power inside.

Either 1) you have a very brief external power short or 2) inside the stereo head unit there is a short which lost its unlock and power

Post by **BEJinFbk** » 21 Mar 2012, 17:31

What you've described is not a common problem.

Are you having any other electrical problems?
This sounds a lot like you may have low voltage issues.
If you just got this car, having the charging system tested
may be a good idea. Got a meter? You can check a lot yourself.

jkasdorp · Post by **jkasdorp** » 22 Mar 2012, 07:22

Ok, got the code from the dealer, turned on the radio, entered the code. Then the radio asked to re-enter the code, wich I did. Then the display showed "system off" and nothing else happens. Wrong procedure? If I have the time I'll pay the dealer a visit.
I did not check the voltages yet, since my Fluke died on me.
No other electrical issues so far, except that the tracs / abs light comes on occasionally.
By the way, just noticed that the unit is a SC-901.

Post by **BEJinFbk** » 22 Mar 2012, 14:08

Did the dealer give you a code based on the VIN?
If the radio is not the original factory unit, it won't be correct.

Pull the radio and take it in so they can use the current radio's info.
You may even get lucky and find the code written on the radio!

But the behavior is still odd. That radio may have problems...

The ABS/TRACS problem is a well known issue. Search it.
The condition is usually caused by failed solder joints in the ABS module.
If you can solder, you can fix it. Or you can use one of the many repair services.
Whatever you do, don't buy a new ABS module from the dealer!
They are waaaay too expensive and the original can be easily fixed.

gapco · Post by **gapco** » 22 Mar 2012, 15:48

Some of the SC901 have this problem where the radio stops playing by freezing on a radio station or a CD. By disconnecting the
power to the radio and reconnecting it after a few moments the radio will work after entering the safety code.

This fault will re occur after some days or even weeks. The fault is that the main microprocessor in the radio looses it's memory. The remedy is to have an authorised Volvo radio repair centre replace the old microprocessor with a new updated
version.

Modified SC901's have a small round skyblue sticker on the top cover of the radio.

jkasdorp · Post by **jkasdorp** » 26 Mar 2012, 07:19

Found the correct code on the unit when I pulled it out. Everything is in good working order again.
Thanks for the help.