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2003silverado reduced engine power comes on . no power at all ,cant go over 30mph.i have replaced throttle body, and accelerator peddle sensor ,(no cure) what could it be ?any help is appreciated. thanks

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1 Answer

Neither the Throttle Body or the APP (Gas Pedel -that never fails)
was the problem

Who diagnosed & replaced all that?

Do you have cylinder misfires (bad coils)?

What codes were there when whatever happened
first started?

Posted on Nov 30, 2012

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6 Suggested Answers

6ya6ya
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Posted on Jan 02, 2017

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  • 64 Answers

SOURCE: 1999 volkswagen stalled

first check cylinder 1 , spark plug, ht leads, coil,

then clean the trottle body with carb cleaner

if that does not work replace the throttle body, comes complete, and do a basic setting on it with diagnostic machine

Posted on Feb 19, 2009

ifixgms
  • 64 Answers

SOURCE: a p0011 code and camshaft sensor replacement did not cure problem

well i know on the v6 that is true you replaced all of them. Not sure of 4 cyl but seems like it should be the same. Also I know on the v6 the variable valve timing set up sometimes did some weird failures triggering a cam sensor code. It could be anything from sludgy oil hanging up in the vvt hub or clogged passages or bad solenoids. but before going into all that(well besides maybe an oil change) I would go for the crank sensor.

Posted on Apr 07, 2009

shocktroop40
  • 155 Answers

SOURCE: bogging and hesitation on acceleration iddle is fine

You definitely covered most of the bases. Considering all you've done so far, I would check into the fuel system next. First, how old is the fuel filter? Has it been changed? Yes, a bad filter can cause the problems your having. Next would be the fuel pressure regulator. You need a fuel pressure gauge to check it, which you should be able to rent from a good auto parts store. That will also tell you how good your fuel pump is, i.e. if the pump can deliver the necessary fuel pressure off idle. After that, I would check the injectors themselves for wear or blockage. A bottle of fuel injector cleaner in the gas tank would be a good idea, cheap, quick, and it wont make anything worse. If all that checks out, check your catalytic converter, a clogged or bad cat will also do what your describing. Good luck.

Posted on Aug 03, 2009

alicantecoli
  • 22219 Answers

SOURCE: I have a 03 gmc envoy. My reduced engine power

sensors on the pedal?? not sure what you mean by paddel though never heard of this term before

Posted on Dec 14, 2009

Testimonial: "03 Envoy:My reduced engine power keeps happening. My car goes 20 mph. Changed throttle body, pedal, wiring. Need new thermostat. Car not heating up."

  • 11 Answers

SOURCE: on a 04 camry with 2.4 ltr engine, can I replace

I think the terms "Throttle Positon Sensor", TPS and "Throttle Body" can be misleading at least in regards to the 04 Camry.

My 04 Camry gave a diagnostic reading of P2121 for my problem "Throttle PEDAL position switch D circuit". However, we changed out the complete Throttle Body/TPS (Toyota Part #22030-0H020) that did NOT fix problem.

The 04 Camry TPS Electronic Module "Throttle Positon Sensor" is factory assembled and riveted to the side of the throttle body. The only way to service/inspect it would be to cut off or drill out the rivets. Not sure you could open the darn thing if you got it off, but that seems to be the only way Toyota sells them!!

Hopefully a new Throttle PEDAL Position Sensor (Toyota Part # 78010-33010 PEDAL ASSY, ACC)
will fix it. This is located under the dash near the accelerator pedal.

So, now I would recommend FIRST to replace the "Throttle PEDAL Positon Sensor" (it is much, much cheaper) and then the Throttle Body/TPS assembly!! Unless of course, you get a diagnostic code as you did for "faulty throttle body!!


Posted on Jan 21, 2010

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1 Answer

Throdlebody and gas peddle out of sink won,t go faster than 30


If you would like help we would need the DTC - diagnostic trouble code .Is their a Reduced Engine Power Mode message showing on the instrument cluster ?
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.
IF you do not know this your best bet would be to take to a qualified repair shop .
DTC P0506
DTC P0507
The throttle actuator control (TAC) motor is controlled by the powertrain control module (PCM). The DC motor located in the throttle body drives the throttle plate. In order to decrease idle speed, the PCM commands the throttle closed reducing air flow into the engine and the idle speed decreases. In order to increase idle speed, the PCM commands the throttle plate open allowing more air to pass the throttle plate. If the actual idle RPM does not match the desired idle RPM within a calibrated time, this DTC sets.

Jan 05, 2017 | Cars & Trucks

1 Answer

Check engine light reduce engine power and traction controll off.


It could be the APP sensors or the throttle body throttle position sensors . What DTC'S - diagnostic trouble codes . Need to test the electrical wiring , 5 volt reference voltage. Drive by Wire Function and diagnostics by Wells
REDUCED ENGINE POWER - mass airflow sensor has nothing to do with this problem .
Throttle Actuator Control (TAC)
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.




Refer to
?€¢
Powertrain Control Module Description for the 4.8L, 5.3L and 6.0L engine


May 09, 2016 | 2006 Chevrolet Avalanche

1 Answer

I changed everything on a 2007 Chevy uplander the camshaft position sensor And the purged sensor And the throttle body and still the check engine light and the reduce engine power came back on


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.
Did you have it checked for DTC's - diagnostic trouble code's related to the reduced engine power ?
All so has APP sensor gas pedal !
Accelerator Pedal Position (APP) Sensor
The accelerator pedal contains 2 individual accelerator pedal position (APP) sensors within the assembly. The APP sensors 1 and 2 are potentiometer type sensors each with 3 circuits:
?€¢
A 5-volt reference circuit


?€¢
A low reference circuit


?€¢
A signal circuit

The APP sensors are used to determine the pedal angle. The engine control module (ECM) provides each APP sensor a 5-volt reference circuit and a low reference circuit. The APP sensors provide the ECM with signal voltage proportional to the pedal movement. The APP sensor 1 signal voltage at rest position is less than 1 volt and increases to more than 4 volts as the pedal is actuated. The APP sensor 2 signal voltage at rest position is less than 0.6 volt and increases to more than 2 volts as the pedal is actuated.
Your best bet is take your vehicle to the dealer !
al

May 03, 2016 | Cars & Trucks

1 Answer

2003 Chevy Trailblazer engine power lose light come on


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

May 04, 2015 | 2003 Chevrolet Chevrolet TrailBlazer

1 Answer

Gm code p2120


Code p2120 is accelerator pedal position sensor APP sensor 1 circuit apparently this is known as the reduced engine power syndrome and is quite common on the avalanche. There is no mechanical linkage from gas pedal to throttle body and it is quite common for the throttle position sensor located on throttle body to mess up and throw this code and also for one of the wires to the throttle position sensor to get hot become brittle and sometimes break. I would start there

Aug 04, 2014 | 2003 Chevrolet Avalanche

1 Answer

Reduced engine power


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.

May 12, 2017 | 2004 GMC Sierra Denali

1 Answer

Have 2006 gmc canyon having trouble with it staying on.3.5 engine starts up,stays on a few seconds then shuts off shows reduced power on panel.won't crank over .have to wait a few minutes then it


REDUCED POWER
Refer to:
• Powertrain Control Module Description for the 2.8L engine
• Powertrain Control Module Description for the 3.5L engine

Throttle Actuator Control (TAC) System
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.

Accelerator Pedal Position (APP) Sensor
The accelerator pedal position (APP) sensor is mounted on the accelerator pedal assembly. The APP is 2 individual APP sensors within one 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.
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 signals, 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.

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.

Have you had it checked for DTC'S - diagnostic trouble codes ?

DTC P2176
The commanded throttle position (TP) is compared to the actual TP. Both values should be within a calibrated range of each other. The powertrain control module (PCM) continuously monitors the commanded and actual TPs. If the values are greater than the calibrated range, DTC P2176 sets.
--------------------------------------------------------------------------------
DTC P2138
The accelerator pedal position (APP) sensors 1 and 2 are located within the accelerator pedal assembly. Each sensor has the following circuits:
• A 5-volt reference circuit
• A low reference circuit
• A signal circuit
This provides the powertrain control module (PCM) with a signal voltage proportional to accelerator pedal movement. The APP sensor 1 signal voltage at rest position is near the low reference and increases as the pedal is actuated. The APP sensor 2 signal voltage at rest position is near the 5-volt reference and decreases as the pedal is actuated.
DTC P2135
The throttle actuator control (TAC) assembly has 2 throttle position (TP) sensors mounted within the assembly. The powertrain control module (PCM) provides individual signal, ground, and 5-volt reference circuits to each sensor. Both sensors operate within a voltage range between 0.35-4.65 volts. When the throttle is opened from 0-100 percent, one sensor signal voltage increases while the other decreases. The signal circuit for TP sensor 1 is referenced to ground, and the signal circuit for TP sensor 2 is pulled up to 5 volts within the PCM.
DTC P2128
DTC P2127
DTC P2125
DTC P2123

Drive by Wire Function and diagnostics by Wells

May 25, 2017 | 2006 GMC Canyon

2 Answers

Check Engine Light & Dashboard Reads Reduced Engine Power


The reduced engine power happens because there is a problem with the electronic throttle control . Some people call it drive by wire ! The gas pedal has sensors inside , position sensors , connected electrical to the PCM - engine computer , the throttle body on the engine has a DC electric motor an also has position sensors . These are also connected to the PCM electrical . The PCM reads the position sensors which indicate how much your pressing on the gas pedal . then hopefully it opens the throttle the same amout .

The throttle actuator control (TAC) system delivers improved throttle response and greater reliability and eliminates the need for mechanical cable. The TAC system performs the following functions:
• Accelerator pedal position sensing
• Throttle positioning to meet driver and engine demands
• Throttle position sensing
• Internal diagnostics
• Cruise control functions
• Manage TAC electrical power consumption
The TAC system includes the following components:
• The accelerator pedal position (APP) sensors
• The throttle body assembly
• The engine control module (ECM)

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.

GM Electronic Throttle Body Circuit Descriptions And Testing Tips

Tons of videos on youtube for these systems , there can be a variety problems , from wiring , worn out sensors , the DC motor , computer etc....

Jun 20, 2017 | 2007 Chevrolet Uplander

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