Charging system
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,629
Likes: 4,074
From: Cape Coral, Florida
You may have a DTC set but these electrical system trouble codes will not illuminate the MIL...you may have a P0621 or 0622 set.
Last edited by C5 Diag; Jun 5, 2026 at 04:14 PM.
Intermediate
Joined: May 2023
Posts: 30
Likes: 2
Check grounds
I just had this pop up on my 06 this weekend. I don't have any codes and the charging system appears to be operating normally. I have an OBDII scanner but not a multimeter so I'll have to run to the parts store to have them check the battery and alternator to rule those out.
There are a couple of posts about this in the forum that say if you battery is good (12V+) with the engine off and over 13V with the engine running, then you may have loose or corroded ground connections to the chassis. One of the posts even has the diagrams of where all the ground connections are.
There are a couple of posts about this in the forum that say if you battery is good (12V+) with the engine off and over 13V with the engine running, then you may have loose or corroded ground connections to the chassis. One of the posts even has the diagrams of where all the ground connections are.
