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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2006 🢒 Equinox 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 DTC P2120

Circuit Description

The accelerator pedal position (APP) sensor 1 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 1 signal voltage is low at rest and increases as the pedal is depressed. When the control module detects that the APP sensor 1 signal or the APP sensor 2 5-volt reference voltage is outside the predetermined range, or the APP sensor 1 voltage is lower than a specified value when the accelerator pedal is in the closed throttle position, DTC P2120 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P2120 Accelerator Pedal Position (APP) Sensor 1 Circuit

Conditions for Running the DTC
    • DTC P2107 is not set.
    • The ignition switch is in the Crank or Run position.
    • The Ignition 1 Signal parameter is more than 5.23 volts.
    • The communication between the throttle actuator control (TAC) module and the powertrain control module (PCM) must be valid.
    • DTC P2120 runs continuously once the above conditions are met.

Conditions for Setting the DTC
    • The APP sensor 1 voltage is less than 0.235 volt or more than 4.487 volts for longer than 100 milliseconds.
        OR
    • The APP sensor 1 5-volt reference voltage is less than 4.54 volts or more than 5.21 volts.
        OR
    • The APP sensor 1 voltage is less than 0.235 volts for longer than 100 milliseconds when the accelerator pedal is at the closed throttle position.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame and/or the Failure Records.
    • The control module commands the TAC system to operate in the Reduced Engine Power mode.
    • A message center or an indicator displays Reduced Engine Power.
    • Under certain conditions the control module commands the engine OFF.

Conditions for Clearing the DTC
    • 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 - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the APP Sensor 1 parameter with a scan tool and with the accelerator pedal in the rest position.

Is the voltage within the specified range?

0.24-2 V

Go to Step 4

Go to Step 3

3
  1. Turn OFF the ignition.
  2. Disconnect the accelerator pedal harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage of the APP sensor 1 5-volt reference circuit with a DMM.

Is the voltage within the specified range?

4.6-5.2 V

Go to Step 6

Go to Step 9

4

Is DTC P2138 also set?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 5

5
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text or as close to the Freeze Frame/Failure Records that you observed.

Did the DTC fail this ignition?

--

Go to Step 6

Go to Testing for Intermittent Conditions and Poor Connections

6
  1. Turn OFF the ignition.
  2. Disconnect the accelerator pedal harness connector, if not done in a previous step.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the APP Sensor 1 parameter with a scan tool.

Is the voltage within the specified range?

0-0.2 V

Go to Step 7

Go to Step 11

7
  1. Connect a fused jumper wire between the APP sensor 1 5-volt reference circuit and the APP sensor 1 signal circuit at the accelerator pedal harness connector.
  2. Observe the APP Sensor 1 parameter with a scan tool.

Is the voltage within the specified range?

4.6-5.2 V

Go to Step 13

Go to Step 8

8
  1. Turn OFF the ignition.
  2. Remove the fused jumper.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage of the APP sensor 1 5-volt reference circuit with a DMM.

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 1 5-volt reference circuit?

5 V

Go to Step 14

Go to Step 16

10

Test the APP sensor 1 signal circuit for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 22

Go to Step 12

11

Test the APP sensor 1 signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 22

Go to Step 19

12

Test the APP sensor 1 signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 22

Go to Step 19

13

Test the APP sensor 1 low reference circuit for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 22

Go to Step 17

14

Test the APP sensor 1 5-volt reference circuit for an open or for high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 22

Go to Step 15

15

Test the APP sensor 1 5-volt reference circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 22

Go to Step 19

16

Test the APP sensor 1 5-volt reference circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 22

Go to Step 19

17

Is DTC U0107 also set?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

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 .

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 .

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 Position Sensor Replacement .

Did you complete the replacement?

--

Go to Step 22

--

21

Replace the throttle body. Refer to Throttle Body Assembly Replacement .

Did you complete the replacement?

--

Go to Step 22

--

22
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

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?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK