App sensor Code 37-14 ...Accelerator Pedal Position Sensor / Performance Problem The following code 37-14 A-B Correlation Code 61-1 battery voltage failure code 62-1battery voltage :...

code p 2138 refers to throttle position (TP) sensor/switch D/E-- voltage correlation=== causes --- wiring -- tp sensor /switch

code p 2122 refers to accelerator pedal (APP) sensor /switch D --low input===causes --wiring short to ground --APP sensor/ switch

also refers to engine control module (ECM) , idle control ---high input===causes ---wiring short to positive --TP sensor--ETS control valve (ETS----electronic throttle system)

code p 0121 has to answers
1--refers to throttle position (TP) sensor/accelerator pedal position sensor A--range /performance problem====causes --accelerator cable adjustment--TP/APP sensor ---wiring
The second reference is the same and the causes are--accelerator cable adjustment--TP/APP switch
(APP is accelerator pedal position)

code p0221 refers to throttle position sensorB/accelerator pedal position (APP) sensor B--range /performance problem====causes accelerator cable adjustment ( broken)--TP/APP sensor
It also refers tp throttle position switch B/ accelerator pedal position (APP) switch B-range/ performance problem===same cause as before.

DTC P2138: Accelerator Pedal Position (APP) Sensor A/B (Throttle Position Sensor D/E) Incorrect Voltage Correlation.

Accelerator pedal position (APP) sensor A and accelerator pedal position (APP) sensor B are potentiometers, and they are installed in the engine compartment.

The APP sensors A and B are operated via the throttle cable to determine the accelerator opening value when the driver presses the accelerator pedal. The accelerator pedal opening value is converted to a signal in APP sensors A and B and transmitted to the engine control module (ECM)/powertrain control module (PCM) to compute the target position. The target position signal is then transmitted to the throttle actuator control module.

APP sensor A is for the primary control, and APP sensor B is a back-up of APP sensor A in case it malfunctions. Both sensors compare their output voltage to each other for malfunction detection.

When the voltage difference of APP sensor B is out of a fixed range for a set period of time, the ECM/PCM detects a malfunction, and a DTC is stored.

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

Here is the definition. You may need to have someone check the accelerator pedal position sensor and the circuit.

P2138 NISSAN Description The Accelerator Pedal Position (APP) sensor is installed on the upper end of the accelerator pedal assembly. The sensor detects the accelerator position and sends a signal to the Engine Control Module (ECM).
Accelerator pedal position sensor has two sensors. These sensors are a kind of potentiometers which transform the accelerator pedal position into output voltage, and emit the voltage signal to the ECM.
In addition, these sensors detect the opening and closing speed of the accelerator pedal and feed the voltage signals to the ECM. The ECM judges the current opening angle of the accelerator pedal from these signals and controls the throttle control motor based on these signals.
Idle position of the accelerator pedal is determined by the ECM receiving the signal from the accelerator pedal position sensor. The ECM uses this signal for the engine operation
such as fuel cut.
Read more: http://engine-codes.com/p2138_nissan.html#ixzz26J3D2x8s

code p2111 throttle actuator control system actuator stuck open. throttle actuator control system circuit malfunction. brake vacuum implausible signal. code p2112 throttle actuator control system actuator stuck closed.throttle actuator control system circuit malfunction. code p2135 accelerator pedal position sensor switch a b voltage correlation. throttle position sensor switch a b voltage correlation. electronic throttle position sensor switch 1 implausible signal. did not see code p210406 that code too long.

P2138 is Throttle Pedal Position Sensor/ Switch D / E Voltage Correlation. Replace the Throttle Pedal Position Sensor/Switch.Remember to have the set code Cleared from the cars computer, this will turn off the check engine light and reset it. Good Luck and have a good XMASS.

If it is a code P0226 I would not consider it a safety issue.

Throttle position (TP) sensor C/accelerator pedal

position (APP) sensor ? - range/performance problem

Possible Causes: Accelerator cable adjustment, TP/APP sensor

Throttle position (TP) switch C/accelerator pedal position

(APP) switch ? - range/performance problem
Accelerator cable adjustment, TP/APP switch

This might only be an adjustment issue--make sure the throttle cable isn't so tight that the throttle cannot fully close.
If the cable is OK, it is probably the accelerator position sensor under the pedal.
There are procedures for testing the unit that I will paste below if you care to try them.

If you just want a shop to fix it, the part is about $50 and labor should only be 30 minutes.

Operation The sensor is made up of the two individual sensors within a single housing. Each sensor has a unique functionality to determine pedal position. The APP system along with the Powertrain Control Module (PCM) is used to calculate and control the amount of acceleration and deceleration through fuel injector control.

Removal & Installation

1. Remove the driver-s side knee bolster.
2. Push down on the small tab and disengage the electrical connector.
3. Remove the pedal bolts and remove the pedal and sensor assembly.
4. Installation is the reverse of removal.
   
   

   

Fig. APP sensor mounting
Testing

1. Install a 3 amp fused jumper wire between the 5-volt reference terminal of the APP sensor and 5 volts. Install a jumper wire between the low reference terminal and a ground.
2. Sweep the sensor through the entire range while monitoring the voltage between the signal terminal and the low reference terminal with a digital multimeter. The voltage should vary between 0.30-4.98 volts without any spikes or dropouts.
3. If the voltage is not within the specified range or is erratic, replace the accelerator pedal assembly.

This is what I find from other webpost..

Condition:
Some customers may comment on an MIL/SES light Illuminated with the" Reduced Engine Power" message or indicator displayed. A technician may find two or more of the following DTCs stored in the ECM:

P060E : Control Module Throttle Position (TP) System Performance

P1516 : Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance

P2135 : Throttle Position (TP) Sensor 1-2 Correlation

P2138 : Accelerator Pedal Position (APP) Sensor 1-2 Correlation

Cause:
A battery voltage drop during the cranking cycle may cause the codes to set and place the vehicle into the reduce engine power mode.

Correction:
Test and charge the battery using the steps below.

Important: A low voltage condition may cause at least two of the following DTCs to set.

P060E : Control Module Throttle Position (TP) System Performance

P1516 : Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance

P2135 : Throttle Position (TP) Sensor 1-2 Correlation

P2138 : Accelerator Pedal Position (APP) Sensor 1-2 Correlation


Perform a Diagnostic System Check. Refer to Diagnostic System Check - Vehicle in SI.
Check for DTCs and review the Freeze Frame/Failure Records to determine if sufficient ignition voltage was present when the DTC set.
- If the ignition voltage was low, then check for a possible battery drain. Refer to Battery Electrical Drain/Parasitic Load Test.

- If the ignition voltage was sufficient when the code set, proceed with normal SI diagnosis for the code(s) set.

Test and recharge the battery using Bulletin 02-06-03-009 or latest version on "Battery Charging Tips'.
Clear all DTCs.