My Chevrolet Captiva 2.4LT has Accelerator Pedal Sensor Position Error P2122 and P2120, how do I solve this error. When the error occurs engine runs stiff and i think the emission system is been affected because the speed goes below 80km/hr

AMBER
the car needs service
the throttle by wire is failing.

common this.

https://www.impalaforums.com/threads/p2122-code-accelerator-or-throttle-body.1818978/

DTC P2122: Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage


the means the DEVICE under right foot is bad./
electronic throttle pedal device.

any shop in town can repair this.
no need for dealers.

Switching on the aircon will rob the engine of a handful of horses but most people most of the time won't notice. Could be the problem goes deep.

By 2007 most vehicles were digital computer controlled so it isn't easy to guess what is going on. I think you need a guy with a good scanner who knows how to use it who can gather and interpret live data.

You need to replace the accelerator pedal position sensor, this is an entire throttle pedal assembly which includes the position sensor. Common fault on both Hyundai and Kia cars. This part should be under your federal emissions warranty.

DTC P2122: Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage

Do you know what electronic throttle control is ?


Part 2 Engine Fault no acceleration Case study P2122 P060D

Electronic throttle control !
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

2009 Chevy Silverado P2138 Accelerator Pedal Position


Circuit/System Description
The throttle actuator control (TAC) system uses two accelerator pedal position (APP) sensors to monitor the accelerator pedal position. The APP sensors 1 and 2 are located within the pedal assembly. Each sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit.
Two processors are also used to monitor the TAC system data. Both processors are located within the engine control module (ECM). Each signal circuit provides both processors with a signal voltage proportional to pedal movement. The processors share and monitor data to verify that the indicated APP calculation is correct.

DTC P0455: Evaporative Emission (EVAP) System Large Leak

The control module tests the evaporative emission (EVAP) system for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge solenoid valve OPEN and the EVAP vent solenoid valve CLOSED. This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge solenoid valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister purge and vent solenoid valves.

P2122 CHEVROLET - Accelerator Pedal Position Sensor 1 Circuit Low Voltage https://www.autocodes.com/p2122_chevrolet.html

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

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

First of all a scan tool is need for this not a code reader, you need to view scan data after you find what code is stored in the PCM. It could have a problem with the powertrain control module, wiring, or the Accelerator Pedal Position (APP) Sensors. Here are a few codes that could set .
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

Your CODE P1276 refer to the Acelerator Pedal Position, Sensor 1 Circuit Range Performance.

Probable cause: Wiring, APP or ECM


GM - P1271 Accelerator Pedal Position Sensor 1-2 Correlation

I also found this... though its for Trailblazers... but may give you a clue:
Reduced Engine Power Message and/or Check Engine Light with any Combination of the following DTCs: P0107 P0112 P0122 P0452 P1120 P1220 P1221 P1271 P1275 P1280 P1481 P1515 P1540 P1633 P1635 P1639 P1682 #PIP3192 - (Oct 18, 2004)

Reduced Engine Power Message and/or Check Engine Light with any Combination of the Following DTCs: P0107 P0112 P0122 P0452 P1120 P1220 P1221 P1271 P1275 P1280 P1481 P1515 P1540 P1633 P1635 P1639 P1682 PCM Repeat.

The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

Condition/Concern:
Reduced engine power message and/or check engine light with any combination of the following DTCs: P0107 P0112 P0122 P0452 P1120 P1220 P1221 P1271 P1275 P1280 P1481 P1515 P1540 P1633 P1635 P1639 P1682

Recommendation/Instructions:
If the SI diagnostics did not isolate a concern, the following information may be helpful:
- Inspect the main engine wiring harness between the PCM and the generator assembly for a potential short to ground. There is a metal wiring harness retainer in this area that secures the main engine harness. If the harness conduit is mispositioned, some of the wiring may become exposed and chaff on the harness retainer. This may eventually cause the exposed circuit to short to ground.

- Inspect the 3 harnesses that connect to the PCM for potential shorts to ground on the metal PCM mounting bracket, just below the PCM. There are plastic harness retainers on the PCM bracket that secure the harnesses to the PCM bracket. If the harness conduit is mispositioned, some of the wiring may become exposed and chaff on the PCM bracket. This may eventually cause the exposed circuit to short to ground.

- If a chaffed circuit is found in either of the above locations, repair the circuit using the necessary SI procedures. Once the circuit is repaired, tape the area of the affected area of the harness to prevent the wires from becoming exposed in the future and secure the harness using the original harness retainer.

This applies to 04:
- 4.2L 5.3L LL8 LM4 Engine with DTC - P2120 or P2122 or P2123 or P2125 or P2127 or P2128 - kw low MIL pedal power reduced #PI01746 - (Feb 17, 2004)
- 4.2L 5.3L LL8 LM4 Engine with DTC - P2120 or P2122 or P2123 or P2125 or P2127 or P2128.

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Condition/Concern:
MIL light on. Reduced Power message on DIC. Possibles DTCs P2120 and/or P2122, P2123, P2127, and P2128.

Recommendation/Instructions:
The APP harness is clipped to the accelerator pedal bracket. The harness may chaff on the upper portion of the accelerator pedal causing a short to ground. Verify the harness is not chaffing on the accelerator pedal. After repairing the short, reposition the harness to ensure no contact between the harness and the accelerator pedal.

Hope helpes.