* Dirty Laser Lens: Dust and grime on the laser lens is the most common cause. The lens needs to be meticulously cleaned. Do not attempt this yourself unless you are comfortable disassembling electronics. It's easy to damage the lens further.
* Faulty Laser Assembly: The laser itself might be failing. This requires replacing the entire laser assembly, a repair that's often more expensive than replacing the entire CD player.
* Problem with the CD Mechanism: There might be a mechanical issue preventing the disc from spinning correctly or being read properly. This could be a worn gear, a broken belt, or other internal mechanical component.
* Internal Wiring: A broken wire or connection within the CD player is also possible, though less common than laser issues.
Since the CD player ejects the disc, this suggests the problem might not be solely with the laser reading the disc, but also potentially with the motor or mechanism.
What NOT to do:
* Don't attempt to clean the laser yourself unless you're experienced with electronics repair. You can easily scratch or damage the lens beyond repair.
* Don't try to force the CD player to function. This could cause further damage.
What YOU CAN do (and should do first):
* Check the CD: Make sure the CD itself isn't scratched or damaged. Try a different, known-good CD.
* Check all connections: Make sure the CD player is securely connected to the car's wiring harness. (This is unlikely to fix an E20 error, but it's a good basic troubleshooting step)
What you SHOULD do (recommended):
* Take it to a car stereo repair shop: They have the tools and expertise to diagnose and repair the CD player correctly, or recommend replacement. The cost of repair might be comparable to buying a replacement aftermarket CD player or a modern Bluetooth receiver.
* Replace the CD player: If the repair cost is high, consider replacing the entire unit. Used parts might be cheaper but carry more risk. An aftermarket stereo system (even a basic one) that plays CDs and connects via Bluetooth offers more features and potentially better reliability for a similar or lower cost than a repair.
The horn and fuses being unrelated to the CD player error is a good indication of a localized issue. Focus your attention on the CD player itself and seek professional help if you're not comfortable with electronics repair.
