Technical OEM Delphi radio occasional no sound except for the subwoofer.


New member
Nov 20, 2021
Hi All,

I've been trying to solve this problem for a couple of years now. My wife's Punto Evo occasionally only plays sound through the subwoofer in the trunk.

The problem does not occur always, it's also not getting worse or better over time. It's best described as follows:

  1. option 1:
  2. switch on the ignition
  3. sound only comes from the trunk
  4. turn the ignition of and on until after a few tries the amp clicks on (the relay is somewhere in the amp itself, you can hear it click) and we have sound coming from all speakers

  1. option 2:
  2. leave the ignition off
  3. turn the radio on with the power button
  4. if no sound, keep pressing the power button until the unit switches off
  5. repeat until it works, keep radio on and start the car

Things I've tried so far were to no avail:

  1. Replaced the Delphi head unit, copied the EEPROM and it's working as it should. Problem did not go away.
  2. Replaced the stock amplifier in the passenger foot well, also no luck.
  3. Checked wiring loom on the back of the radio and amplifier.
  4. Scanned the car for error codes with MultiEcuscan, both ELM as with the A3 - Yellow adapter cable. No codes popped up, everything seems fine.
Does anyone have more information on the workings of the Delphi F199 head unit or the Punto Evo audio system. Does it check the connections for errors before it decides to turn on? I really don't feel like opening all the door panels looking for a broken wire, but that is about the only thing I can think of now.