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Home >> Pontiac >> 2007 >> Vibe Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - DTC P0452 To DTC P2138 >> DTC P2123 >> Test Description
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Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. 1:  The Diagnostic System Check - Vehicle prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
  2. 4:  This step tests for a short to voltage on the APP sensor 1 signal circuit. With the sensor disconnected, the signal circuit should be near zero volts.
DTC P2123

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Powertrain Control Module Connector End Views  or  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 APP Sensor 1 parameter with a scan tool.
Is the APP sensor 1 parameter more than the specified value?		 4.8 V Go to Step 4  Go to Step 3 
3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 90 seconds.
  3. 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 4  Go to Intermittent Conditions
4 
  1. Disconnect the accelerator pedal position (APP) sensor.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the APP sensor 1 parameter with a scan tool.
Is the voltage more than the specified value?		 0 V Go to Step 6  Go to Step 5 
5
  1. Connect a test lamp between the low reference circuit of the APP sensor 1 and B+.
  2. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?		 - Go to Step 9  Go to Step 7 
6 Test the signal circuit of the APP sensor 1 for short to voltage. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 11  Go to Step 10 
7 Test the low reference circuit of the APP sensor 1 for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 - Go to Step 11  Go to Step 8 
8 Test for an intermittent and for a poor connection at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 - Go to Step 11  Go to Step 10 
9 Replace the APP sensor 1. Refer to Accelerator Pedal Position Sensor Replacement .
Did you complete the replacement?		 - Go to Step 11  -
10 Replace the PCM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 11  -
11
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 90 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 12 
12 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
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