Error message reads Cal Err. What does it mean and what corrective action is necessary?

Radio Displays CAL or CAL ERR

Step
Action
Yes
No
Schematic Reference: Radio/Audio System Schematics
1
Did you perform the Diagnostic System Check-Entertainment System?
YES Go to Step 2
NO Go to Diagnostic System Check - Entertainment System
2
Turn ON the ignition, with the engine OFF.
Turn ON the radio.
Does the radio operate normally?
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
Go to Step 3
3
Program the radio. Refer to Service Programming System (SPS) .
Turn OFF the ignition.
Turn ON the ignition, with the engine OFF.
Turn ON the radio.
Does the radio display CAL ERR?
Go to Step 4
Go to Step 5
4
Important: Reprogram the radio. Refer to Service Programming System (SPS) in Programming.
Replace the radio. Refer to Radio Replacement .
Did you complete the replacement?
Go to Step 5
--
5
Operate the system in order to verify the repair.
Did you correct the condition?
System OK
Go to Step 2

Question edited for clarity.
Question moved to model category.

It appears to be a software error that only the dealership or an auto electrician can fix!

https://www.google.com/search?q=2002+trailblazer+radio+cal+error

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ERR means "ERROR" in reading the disk, if all disks do this it's time for a new player.

Unfortunately the CAL ERR is inside the radio and it requires a scan tool to reprogram. There are shops that are not a dealer that can do this programming. There is no code or sequence that I can give you to unlock or fix this. If there was, rest assured I would, but there is not. check with local stereo shops

I’m happy to help further over the phone at https://www.6ya.com/expert/dennis_7c5f8bf265aab5e9

ERR message on GM Delco CD Radio after ejecting CD Now CD will not work

read that thread i linked

it's possible to reset that GM radio by removing the fuse waiting a while for it to reset then re-installing the radio fuse

otherwise, it's time for an aftermarket head unit if that err 9 returns

Visit http://www.troublecodes.net/OBD2/

dear friend- the error code means the lazer is not reading your cd,if it is a pirate cd it might be the problem,or the lens must be cleaned.

try different KnownGood cd and if still an issue your head unit needs repair internally .(not worth it)

this generally means the laser is either dirty or the cd player is shot, err 01 is a disc reading problem. Try cleaning lens with cleaning disc first if this does not help i would replace the unit with another. i would recommend replacing it with a cheap aftermarket stereo.

the security on the radio has been tripped you need to take it to a GM dealer and have them run a code to unlock it CAL means calibrate