Conditions for Clearing the DTC

2006 Buick Allure CXSSECTION Conditions for Clearing the DTC
WARNING: This page is about a different variant/trim than selected.
  • 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.
DTC P2120

Step Action Values Yes No
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Powertrain Control Module (PCM) Connector End Views and Engine Controls Connector End Views
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle
2
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the accelerator pedal position (APP) sensor 1 voltage with the accelerator pedal in the rest position with a scan tool.
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 APP harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage of the APP sensor 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. 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 6  Go to Testing for Intermittent Conditions and Poor Connections
6
  1. Turn OFF the ignition.
  2. Disconnect the accelerator pedal harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the APP sensor 1 voltage parameter with a scan tool.
Is the voltage at the specified value?
0 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 voltage parameter with a scan tool.
Is the voltage within the specified value?
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 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 with 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
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.