I have a 2007 Chevy Tahoe. The engine light came on and stayed on. When checked, here is the code that appeared: TPS/PEDAL POSITION SENSOR ACKT RANGE/PERF. I am assuming the code deals with the adjustable throttle and brake pedal. My concern is that the throttle may malfunction and possibly cause me to wreck. Can you provide any insight as to the potential danger and the cost to replace the sensor?

Problem with electronic throttle control . search reduced engine power on youtube . Have the vehicle checked for DTC'S - diagnostic trouble codes . And don't listen to advice on forums ,they have no clue . It's probably a TPS - throttle position sensor or one of the sensors in the APP
The APP sensor is fixed to the throttle body of the electronic throttle control system with intelligence (ETCSi). The functional principle to the AAP sensor involves conversion of the accelerator pedal movement into a voltage signal.
Inside a Car - Accelerator Pedal Position Sensor vs ... I would tell you to take it to a qualified repair shop but most people don't want to hear that . Untill it's too late .

P1121 GMC - Throttle Position Sensor Circuit Intermittent High Voltage
This codes has nothing to do with APP - accelerator pedal position sensor . This has to do with the throttle body - TPS throttle position sensor . These have know problems ,the sensor an broken wire at throttle body , an when this happens the cruise control wont work . The throttle works by a DC motor controlled by the PCM - engine computer .

Replacing TPS will reset the light but will stay in memory until the computer is reset. For help to change throttle body sensor check out you tube :How To Install Replace Throttle Position Sensor Chevy Silverado GMC Sierra.

It is more then likely a wiring problem or Throttle position sensor or the electric motor in the throttle body ! Pt 2 2007 Chevy 2500HD Reduced Engine Power Warning Fault Code P1516... Drive by Wire Function and Diagnostics by Wells

It's the throttle position sensor (TPS) on the throttle body.

No messaage of reduced engine power ? Your vehicle has electronic throttle control . Has four position sensors , two are located in the gas pedal ,an two in the throttle body . The PCM uses these sensor to know how much to open the throttle plate ,allowing more air into the engine . How did you read this code an where did you read it's definition at ? This is not a code for your vehicle . Some time cheap code readers get them wrong .
DTC P2120: Accelerator Pedal Position (APP) Sensor 1 Circuit
DTC P2122: Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage
DTC P2123: Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage
DTC P2125: Accelerator Pedal Position (APP) Sensor 2 Circuit
DTC P2127: Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage
DTC P2128: Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage
DTC P2138: Accelerator Pedal Position (APP) Sensor 1-2 Correlation

DTC P1516: Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance
DTC P2101: Throttle Actuator Position Performance
DTC P2119: Throttle Closed Position Performance
DTC P2176: Minimum Throttle Position Not Learned

If one of this position sensors is bad it will throw the PCM into a
Reduced Engine Power Mode
When the ECM detects a condition with the TAC system, the ECM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
• Acceleration limiting--The ECM will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.
• Limited throttle mode--The ECM will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.
• Throttle default mode--The ECM will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.
• Forced idle mode--The ECM will perform the following actions:
- Limit engine speed to idle by positioning the throttle position, or by controlling the fuel and spark if the throttle is turned off.
- Ignore the accelerator pedal input.
• Engine shutdown mode--The ECM will disable fuel and de-energize the throttle actuator.


017 Accelerator Pedal Position Sensors
Drive by Wire Function and diagnostics by Wells

Codes don't always mean a bad senors. One new TPS sensor would have me moving on to something else. Put a scan tool on it and not just a code reader. Check fuel pressure with the gauge on the windshield as you drive.

Pt 1 2007 Chevy 2500HD Reduced Engine Power Warning Fault Code P1516...

There are a number of these type videos on youtube ! Do you have a DVOM - digital volt ohm meter ? Find a wiring diagram at http://www.bbbind.com/free_tsb.html Three are two position sensors on the gas pedal an two on the throttle body . Find videos on test TPS - throttle position sensors , check the circuits too the PCM an from the gas pedal to the PCM . You can also check motor circuit as well .
GM Reduced Engine Power Mystery Solved

Drive by Wire Function and diagnostics by Wells