Which parts fail
Components named in complaints (battery, alternator, wiring, ignition, instrument cluster, infotainment).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2005 Cadillac STS owners, lightly cleaned up (personal details are redacted by NHTSA).
Tl* the contact owns a 2005 Cadillac STS. While driving 35 MPH, the vehicle shook and the check engine light illuminated. The vehicle was driven back to the contact's residence and smoke emitted from the engine. The vehicle was able to restart. The vehicle was towed to an independent mechanic who diagnosed that the ignition coil had total meltdown surrounded by small flames, and the fuse was blown for the odd injectors. A fire report was not filed and there were no injuries. The vehicle was repaired. The manufacturer was notified of the failure. The failure mileage was 82,920.
My 2005 Cadillac STS brakes locked up and caused my car to crash. After research I am showing that there was a recall regarding the brake system. In addition, when changing gears you can hear the gears changing from the outside of the car. I researched this as well and apparently there is a defect and recall on the axle. I am not happy about this vehicle that I just purchased for alittle over 7 months. There is also an electrical problem. As I am driving, the hood ajar light comes on and there is no sign of my hood being ajar. In addition, the transmission seems as thought it is going out as well. Before I consult with an attorney I wanted to first give GMC an opportunity to resolve this issues. My vehicle has less than 100,000 miles. Also, please note that due to the electrical problem, my reverse lights has never worked. The unknown other would be the axle and transmission.
Dt: the contact's wife drove the vehicle to the grocery store. She parked the vehicle and went in the store. When she came out she noticed people were looking over an embankment. She realized then that the car had rolled backward over the embankment. A tow truck came and pulled the vehicle up, and then the car was driven home. The engineer at the dealership checked the vehicle and said there was nothing wrong with the vehicle. However the contact felt that the electrical system was faulty. The consumer stated the vehicle has a new keyless ignition system which allows the vehicle to be left in neutral rather than park when the driver exits the vehicle. Updated 01/04/06.
Dt*: the contact stated while driving at 45 MPH smoke was detected inside the vehicle. Fifteen minutes later the vehicle was engulfed with smoke. The occupants got out of the vehicle. After a few minutes they got back in the vehicle and drove it home. The vehicle was taken to a dealership the following morning, diagnostics test were performed on the vehicle. The problem was the wiring and the module under the seat had melted. The repairs have been made. The manufacturer has been notified. The consumer was told the wiring was routed incorrectly updated 03/17/06.
The consumer has problems with the vehicle not wanting to start. The consumer was told that since the vehicle is completely electric that sometimes the circuits or transmitters blow out, 2005 Cadillac STS. While approaching a red light the brakes failed and the vehicle's speed increased. The consumer purposely ran into a divider to stop the vehicle. The vehicle was towed to the dealer where it remained for 45 days.
After leaving restaurant got into car and adjusted driver seat, proceeded to exit,approached stop light, then heard faint popping sound then smelled odor and saw smoke.immediately pulled into adjacent restaurant across street,exited vehicle and car was on fire. An employee at restaurant advised to move away from car fearing an explosion. Immediately called 911 and was dispatched to local fire dept.
Tl* the contact owns a 2005 Cadillac STS. The contact stated that the vehicle failed to start without warning. The failure was persistent. The vehicle was not diagnosed nor repaired. The contact had the battery changed, but the failure recurred. The manufacturer was not notified of the failure. The failure mileage was approximately 64,000.
While driving down the street in my Cadillac STS a (service electric system) warning flashed on my dash. A few moments later everything electric in my car started to shut down. The radio, power steering, lights, and finally the engine. I cruised to the side of the road and put the car in neutral and engaged the emergency brakes.
Just bought the vehicle used and I hear a noise coming from the rear back of the car. The key fob wasn't working correctly and drained the battery and I had to buy a new battery. I really don't know what wrong with the vehicle but its driveable for now besides the slight banging noise. It need to be checked for recalls.
The car has had several documented electrical and mechanical failures. Over the past 2 years the car has been shutting down automatically in the middle of traffic. The display shows 'engine power reduced' and is followed by other messages like 'service anti-lock brake sys' or 'service radar' or service stability sys and traction control.' before the car shuts down the traction control is automatically disabled. I have had to bring the car in for the same symptom 4 different times. The in-service dates that were described and documented for this problem are as follows: 1.)February 22, 2008 ' 'poor drag on c102 connector under hood' 2.)April 24, 2009 ' 'failed converter' 3.)October 1, 2009 ' 'ECM failed' 4.)May 5, 2010 ' 'reprogram PCM' all of the above were serviced by classic Cadillac Saab. Each time they fix something new but the same symptom continues to occur. …
Electrical complaints in other STS years
Frequently asked questions
How common are electrical problems on the 2005 Cadillac STS?
NHTSA has 23 complaints about the electrical system of the 2005 Cadillac STS, 23% of the model year's 101 complaints. The component named most often is ignition (1 mentions).
Is there a recall for 2005 Cadillac STS electrical problems?
No. NHTSA lists no electrical system recall for the 2005 Cadillac STS, though it has 3 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2005 Cadillac STS electrical problems start?
Half of the complaints with a recorded mileage happened before about 64,000 miles, and 30% before 25,000 miles.
Is it dangerous?
Owners linked 3 crashes, 3 fires and 0 injuries to electrical system problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.