After digging around some of the other GM and VW sites (since both GM and VW use Monsoon radio gear), I finally came across a Pontiac Grand Am and a GM F-Body site that shows some common Monsoon errors.

Here's the list (from the Grand Am site):

E20 - Focus Error . This could occur if the disc is dirty, in rough roads or if the humidity is high.

E21 - Tracking Error. (Tracking error can be caused by blemishes on the disc)

E22 - Motor Error. The CD motor needs service.

E23 - Communication Error

E30 - Focus Error (Optics focus error may be due to moisture, upside down disc or empty cart)

E31 - Tracking Error ( Tracking error can be caused by blemishes on the disc)

E32 - Load / Unload motor Problem.

E33 - CD Changer Communication Error.

E34 - CD Changer Door Open

E35 - Changer Cartridge Empty.

Here's the common solutions for the E3x series of errors (from the F-Body site):

E30 - Focus Error Cause(s): The CD player cannot focus on the disc or there is an internal focus problem. Correction(s): Try cleaning the disc or using a new disc. Make sure the disc is loaded correctly. The road could be too rough or there is too much humidity. If there is still an error, service the unit at an ACDelcoR Service Center.

E31 - Tracking Error Cause(s): There is a problem with reading the disc. Correction(s): Try cleaning the disc or try using a new disc. Make sure the disc is loaded correctly. The road could be too rough or there is too much humidity. If there is still an error, service the unit at an ACDelcoR Service Center.

E32 - Motor Error Cause(s): The CD motor is not handling the compact disc properly or defective magazine mounting screws are interfering with the mechanism. Correction(s): Reload the magazine. If there is still a problem, replace the magazine. If the problem continues, back out the mounting screws. If the condition is corrected, replace the screws with shorter screws or add washers to the existing screws. If this condition still exists, service the unit at an ACDelcoR Service Center.

E33 - CD Changer Communication Error Cause(s): There is a vehicle/radio communication problem or internal radio communication problem. Correction(s): Disconnect battery voltage to the radio and then reconnect after a few minutes. If there is still an error, determine if the problem is with the radio, the harness or the changer. Inspect for correct voltage at all connectors. If there is still an error, service the unit at an ACDelcoR Service Center.

E34 - Changer Door Open

E35 - Changer Magazine Empty

Steve