: 2006 DTS "Starting Disabled Service Throttle System"

05-27-13, 11:40 AM
Today while starting to go up a very steep hill my 2006 DTS died. No sputter or warning of any sort, just died. The message center displayed "Starting Disabled Service Throttle System." After the vehicle rolled to a stop I turned the key off them turned it back on and tried to start. Did not try to crank or anything and the message still displayed. There was no check engine light or any other lights or gauges out of the ordinary. I was in a relatively remote area while on a Sunday drive and didnt want to wait and pay for a tow or anything so I disconnected the battery and reconnected it to get the vehicle started. It started like normal and ran perfect all the way back home. When I returned home I took it to the dealership and asked them to take a look, they could not find anything wrong so I paid $25 for diagnosis and was sent on my way. Since then the car has been running completely normal. I could not find any info at all regarding it except for a TSB #224566 related to engine cooling, but no information on a cause or a solution.

I now reach out to the masses of these forums to aid me in solving why my car did this? Please help, thanks!

05-27-13, 02:11 PM
I found there is a TSB Number: 4559 relating to that problem... but I don't have access to read it.

05-27-13, 07:26 PM
#PIC4559A: Engine Power Reduced Or Starting Disabled Service Throttle - (Sep 18, 2008)
Subject: Engine Power Reduced or Starting Disabled Service Throttle
Models: 2006- 2009 Buick Lucerne
2006- 2009 Cadillac DTS

This PI was superseded to update model years and Recommendation/Instructions. Please discard PIC4559.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
A customer may comment about one or more of the following concerns. These concerns may be intermittent:
• Malfunction Indicator Lamp (MIL)/ Check Engine Light is illuminated
• ENGINE POWER REDUCED or STARTING DISABLED SERVICE THROTTLE messages displayed on the Driver Information Center (DIC)
• The engine will not start
One or more of the following DTC may be stored:
• P0452 Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage
• P0650 Malfunction Indicator Lamp (MIL) Control Circuit
• P2120 Accelerator Pedal Position (APP) Sensor 1 Circuit
• P2122 Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage
• P2123 Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage
• P2125 Accelerator Pedal Position (APP) Sensor 2 Circuit
• P2127 Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage
• P2128 Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage
• P2138 Accelerator Pedal Position (APP) Sensor 1-2 Correlation

The cause may be poor electrical connections in C111/ X111 Body Harness to the Engine Harness.


Inspect C111/ X111 for poor connections. Begin with inspecting the lever lock for damage and for it being completely locked. Open the connector and inspect for bent male pins and spread female pins. Gently tug on each wire going into and out of the connector to ensure each terminal is locked into the connector, and that the terminals are not pushing out when the connector is closed and the lever is locked. Remove pins for

C111 (38 Cavities) Engine harness to the body harness, near left front of vehicle