DTC 21. Pontiac GTO 2004

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 2004 🢒 GTO 🢒 DTC 🢒 DTC 21

Conditions for Setting the DTC

With the ignition in either the Accessories position or the ON position, DTC 21 will set to indicate that an error message has been received from the CD Changer due to an internal mechanical error.

Diagnostic Aids

This error may indicate the following:

•	Mechanism has an internal fault

•	Conditions were too severe for the mechanism to operate properly

•	Mechanism may operate properly after conditions improve

Test Description

The numbers below refer to the step numbers on the diagnostic table.

Tests the operation of the CD loading mechanism

Step	Action	Yes	No
1	Switch the audio system ON. Select CD Mode. It may be necessary to try and load a CD. Does a Mechanism Error appear on the display of the audio system?	Go to Step 2	System OK
2	Replace the audio system head unit. Refer to Radio Replacement . Did you complete the repair?	Go to Step 3	--
3	Use the scan tool in order to clear the DTCs. Turn the ignition OFF, then ON again and wait 30 seconds with the radio ON. Does the DTC reset?	Go to Step 2	System OK

Step

Action

Yes

Switch the audio system ON.
Select CD Mode. It may be necessary to try and load a CD.

Does a Mechanism Error appear on the display of the audio system?

Go to Step 2

System OK

Replace the audio system head unit. Refer to Radio Replacement .

Did you complete the repair?

Go to Step 3

Use the scan tool in order to clear the DTCs.
Turn the ignition OFF, then ON again and wait 30 seconds with the radio ON.

Does the DTC reset?

Go to Step 2

System OK