The accelerator pedal position (APP) sensor 2 is a potentiometer type sensor with the following three circuits:
| • | A 5-volt reference circuit | 
| • | A low reference circuit | 
| • | A signal circuit | 
The control module provides the APP sensor a 5-volt reference circuit and a low reference circuit. The APP sensor then provides the control module a signal voltage proportional to pedal movement. The APP sensor 2 signal voltage is low at rest and increases as the pedal is depressed. When the control module detects that the APP sensor 2 signal or the APP sensor 5-volt reference voltage is outside the predetermined range, DTC P2125 sets.
| • | DTC P2107 is not set. | 
| • | The ignition is ON. | 
| • | The ignition voltage is more than 5.23 volts. | 
| • | The APP sensor 2 voltage is less than 0.235 volt or more than 4.487 volts. | 
| OR | 
| • | The APP sensor 2 5-volt reference voltage is less than 4.54 volts or more than 5.21 volts. | 
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. | 
| • | The malfunction indicator lamp (MIL) will not illuminate. | 
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records. | 
| • | The driver information center, if equipped, may display a message. | 
| • | A current DTC Last Test Failed clears when the diagnostic runs and passes. | 
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. | 
| • | Clear the DTC with a scan tool. | 
Step  | Action  | Values  | Yes  | No  | 
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module Connector End Views and Engine Controls Connector End Views  | ||||
1  | Did you perform the Diagnostic System Check-Engine Controls?  | --  | Go to Step 2  | |
2  | 
 Is the voltage with the specified range?  | 0.24-2 V  | Go to Step 4  | Go to Step 3  | 
3  | 
 Is the voltage within the specified range?  | 4.8-5.2 V  | Go to Step 6  | Go to Step 9  | 
4  | Is DTC P2138 also set?  | --  | Go to Step 5  | |
5  | 
 Did the DTC fail this ignition?  | --  | Go to Step 6  | Go to Intermittent Conditions  | 
6  | 
 Is the voltage within the specified range?  | 0-0.2 V  | Go to Step 7  | Go to Step 11  | 
7  | 
 Does the scan tool indicate the APP sensor 2 voltage is within the specified range?  | 4.6-5.2 V  | Go to Step 13  | Go to Step 8  | 
8  | 
 Is the voltage within the specified range?  | 4.6-5.2 V  | Go to Step 10  | Go to Step 9  | 
9  | Does the DMM indicate voltage less than the specified value on the APP sensor 2 5-volt reference circuit?  | 5 V  | Go to Step 14  | Go to Step 16  | 
10  | Test the APP sensor 2 signal circuit for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 12  | 
11  | Test the APP sensor 2 signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 19  | 
12  | Test the APP sensor 2 signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 19  | 
13  | Test the APP sensor 2 low reference circuit for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 17  | 
14  | Test the APP sensor 2 5-volt reference circuit for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 15  | 
15  | Test the APP sensor 2 5-volt reference circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 19  | 
16  | Test the APP sensor 2 5-volt reference circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 19  | 
17  | Is DTC P1518 also set?  | --  | Go to Step 18  | |
18  | Test for an intermittent and for a poor connection at the accelerator pedal harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 20  | 
19  | Test for an intermittent and for a poor connection at the throttle body harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?  | --  | Go to Step 22  | Go to Step 21  | 
20  | Replace the accelerator pedal assembly. Refer to Accelerator Pedal Replacement . Did you complete the replacement?  | --  | Go to Step 22  | --  | 
21  | Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?  | --  | Go to Step 22  | --  | 
22  | 
 Did the DTC fail this ignition?  | --  | Go to Step 2  | Go to Step 23  | 
23  | 
 Important: Be aware that repairing one individual condition may correct more than one DTC. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?  | --  | System OK  | |