2003 GMC throttle position sensor

Do you know what drive by wire is ? electronic throttle control ? Reduced power light on , DTC'S - diagnostic trouble codes stored in the PCM Chevy GMC Code P2135 TPS Problems Watch a few videos on these systems , the gas pedal has sensors , the throttle body does as well , have seen broken wires at connectors . Drive by Wire Function and diagnostics by Wells

Your Denali has Throttle Actuator Control (TAC) System - Electronic throttle control ! Are there any messages on the driver information center ? Reduced engine power ?
Reduced Engine Power Mode When the PCM detects a condition with the TAC system the PCM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
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Acceleration limiting--The control module will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.

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Limited throttle mode--The control module will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.

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Throttle default mode--The control module will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.

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Forced idle mode--The control module will perform the following actions:

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Limit engine speed to idle by positioning throttle position, or by controlling fuel and spark if throttle is turned off.

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Ignore accelerator pedal input.

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Engine shutdown mode--The control module will disable fuel and de-energize the throttle actuator.

You need to have it checked for DTC'S - diagnostic trouble codes , probably a accelerator pedal position (APP) sensor or TPS - throttle position sensor !

Hi Steve , your vehicle has electronic throttle control . I don't know if you are aware of this. The gas pedal have position sensors an a wiring connector with 4-6 wires .these wires are connected to the engine computer . an there is a electric motor on the throttle body assembly , the computer opens an closes the throttle . You probably have codes stored in the engine computer .
Reduced Engine Power Mode When the PCM detects a condition with the TAC system the PCM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:
?€¢
Acceleration limiting--The control module will continue to use the accelerator pedal for throttle control; however, the vehicle acceleration is limited.

?€¢
Limited throttle mode--The control module will continue to use the accelerator pedal for throttle control; however, the maximum throttle opening is limited.

?€¢
Throttle default mode--The control module will turn off the throttle actuator motor and the throttle will return to the spring loaded default position.

?€¢
Forced idle mode--The control module will perform the following actions:

-
Limit engine speed to idle by positioning throttle position, or by controlling fuel and spark if throttle is turned off.

-
Ignore accelerator pedal input.

?€¢
Engine shutdown mode--The control module will disable fuel and de-energize the throttle actuator.

Drive by Wire Function and diagnostics by Wells

the black thing.

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

Have the vehicle checked for DTC'S - diagnostic trouble codes ! Do you know what electronic throttle control is ? The gas pedal assembly has electrical connector an sensors inside ,hooked to the PCM / ECM - engine computer . The engine computer uses these position sensors inputs to control the DC motor on the throttle body to open the throttle plate to control the speed . Plus there are position sensors inside the throttle body to input PCM/ECM to see if it's calculations are corect . Your best bet maybe to take it to a qualified repair shop .
Drive by Wire Function and diagnostics by Wells

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

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

Check the vehicle for DTC'S - diagnostic trouble code's should be the first step in diagnosing this problem . But a tune - up not ! Reduced enging power is caused by a problem with the electronic throttle control . If you are not familiar with this ,your best bet would be to take to a qualified repair shop.
REDUCED ENGINE POWER: Refer to Powertrain Control Module Description in Engine Controls - 4.8L, 5.3L, and 6.0L

Throttle Actuator Control (TAC) Overview
The throttle actuator control (TAC) system uses vehicle electronics and components to calculate and control the position of the throttle blade. This eliminates the need for a mechanical cable attachment from the accelerator pedal to the throttle body. This system also performs the cruise control functions as well.
The TAC system components include, but are not limited to the following:
• The accelerator pedal position (APP) sensors
• The throttle body
• The powertrain control module (PCM)
Each of these components interface together to ensure accurate calculations and control of the throttle position (TP)
Accelerator Pedal Position (APP) Sensor
The APP sensor is mounted on the accelerator pedal assembly. The APP is actually 2 individual APP sensors within 1 housing. There are 2 separate signal, low reference, and 5-volt reference circuits. APP sensor 1 voltage increases as the accelerator pedal is depressed. APP sensor 2 voltage decreases as the accelerator pedal is depressed.

One of these sensors could be sending conflicting data to the PCM - engine computer .

Reduced Engine Power Mode
When the PCM detects a problem with the throttle actuator control (TAC) system the PCM enters one of the following Reduced Engine Power Modes:
• Acceleration Limiting--The control module will continue to use the accelerator pedal for throttle control, however the vehicle acceleration is limited.
• Limited Throttle Mode--The control module will continue to use the accelerator pedal for throttle control, however the maximum throttle opening is limited.
• Throttle Default Mode--The control module will turn off the throttle actuator.
• Forced Idle Mode--The control module will perform the following actions:
- Limit engine speed to idle by positioning throttle position, or by controlling fuel and spark if throttle is turned off.
- Ignore accelerator pedal input.
• Engine Shutdown Mode--The control module will disable fuel and de-energize the throttle actuator.

Throttle Body Assembly
The throttle body for the throttle actuator control (TAC) system is similar to a conventional throttle body with several exceptions. One exception being the use of a motor to control the throttle position instead of a mechanical cable. Another exception is the throttle position (TP) sensor. The TP sensor is mounted in the throttle body assembly. The TP sensor is 2 individual TP sensors within the throttle body assembly. Two separate signal, low reference, and 5-volt reference circuits are used to connect the TP sensors and the powertrain control module (PCM). TP sensor 2 signal voltage increases as the throttle opens. TP sensor 1 signal voltage decreases as the throttle opens.

po455 is Probable Cause[s]

1. Defective, loose or missing fuel cap
2. EVAP canister broke, hose cracked or not connected
3. Purge or vent solenoid defective
4 . Vacuum leak at engine po121 code po121 means Throttle Position Sensor/Switch A Circuit Range/Performance Problem . it is usually indicative of a faulty throttle position sensor or faulty wiring harness in the engine bay.

I had the same problem with my 2003 denali and came to find out that it was the battery causing the problem. the battery with sufficient power will dictate the tps. if the battery is low or bad, it won't have enough juice to allow the tps to. work. get your battery checked.