: Service theft system

08-23-11, 02:55 PM
I have an 05 V for my DD. 56,000 mi.

Car runs good except for the following problem:

On occasion (once per day) the service theft system error appears. After this, the following symptoms are present:
- Traction control turns off. Cannot turn it back on.
- Cannot use XM band radio.
- Engine temp. gauge and fuel level gauge are intermittently active.
- Radio/CD player cut out intermittently.

I noticed that the problem only occurs during the day and in warm temperatures. I tried covering up the sun load sensor on the dash but this did not help.

I have installed the Auxiliary Audio Input by cutting the XM wires. The problems here seemed to appear shortly after I performed the install.

Anybody have any ideas on what this could be?

10-18-11, 06:12 PM
I have the same problem. I live in LA, and it gets hot on the old Black, 2005 STS. I get random errors like service theft system, hood open, check airbag. Nothing is the matter and the dealer checked the codes and said something weird like they see that the codes happened, but there seems to be nothing wrong. I have done no modifications to the XM, so that didn't do it...
I thought that the heat might be affecting something, I bought this car from my dad, who lives in a cooler climate and he reported no problems.
Would love to figure out the fix for this...

10-18-11, 07:21 PM
My guess is a bad ground.

See attached.

11-26-11, 07:21 PM
I have a 2005 CTS 5Speed and have the exact same thing in this order -

- Service Anti Theft System message appears
- Anti-Theft lock lights up
- Traction Control Lights goes on
- After the engine warms up, thermostat and fuel guage quit working
- Radio sound intermittently starts to fade out

Where would you start to find the bad ground? Could be anywhere. Anyone have any luck?

11-26-11, 08:42 PM
The most likely grounds in this case include: (1) the negative battery cable (even if the car will start, etc.); (2) the one located just below the metal rod that holds the hood open; (3) the two grounds bolted to the back of the passenger side cylinder head; and (4) the one bolted to the back of the driver's side cylinder head. Clean and file, or sand all affected metal surfaces; and star washer are your friend.