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Home >> Pontiac >> 2007 >> Vibe Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - DTC P0010 To DTC P0128 >> DTC P0123 >> 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. 2:  This step determines if DTC P0123 is the result of a hard failure or an intermittent condition.
  3. 6:  The TP sensor signal circuit carries a 5-volt bias that can be measured with the DMM. If the measured voltage is near zero there is an open or a faulty PCM. If the voltage is near 5 volts, the circuit is OK. If the voltage is more than 5 volts, there is a short to voltage on the input circuit.
DTC P0123

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  With the throttle closed, select the TP sensor parameter on the scan tool.
Is the TP sensor percentage within the specified value?		 7-11% Go to Step 3  Go to Step 4 
3
  1. Perform the scan tool Clear DTC Information function.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Freeze Frame conditions as specified.
Does DTC P0123 set?		 - Go to Step 4  Go to Diagnostic Aids
4 Is a DTC P0453 also set? - Go to Step 8  Go to Step 5 
5
  1. Disconnect the throttle actuator control (TAC) module electrical connector.
  2. Connect a test lamp to B+ and the ground circuit of the throttle position (TP) sensor.
Did the test lamp illuminate?		 - Go to Step 6  Go to Step 9 
6 
  1. Connect a DMM to the TP sensor 1 input circuit at the harness connector.
  2. Turn ON the ignition, with the engine OFF.
Is the input circuit voltage within the specified value?		 4.9-5.1 V Go to Step 10  Go to Step 7 
7
  1. Test for an open or a short to voltage in the TP sensor 1 input circuit.
  2. Repair the circuit as necessary. Refer to Wiring Repairs .
Did you find and correct a condition?		 - Go to Step 14  Go to Step 12 
8
  1. Test for an open in the TP sensor 1 ground circuit between SP108 and the powertrain control module (PCM).
  2. Repair the circuit as necessary. Refer to Wiring Repairs .
Did you find and correct a condition?		 - Go to Step 14  Go to Step 12 
9
  1. Test for an open in the TP sensor 1 ground circuit between SP108 and the TAC module.
  2. Repair the circuit as necessary. Refer to Wiring Repairs .
Did you find and correct a condition?		 - Go to Step 14  Go to Step 10 
10
  1. Test for an intermittent or a poor electrical connection at the TAC module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
  2. Repair as necessary.
Did you find and correct a condition?		 - Go to Step 14  Go to Step 11 
11 The TP sensor in the TAC module is faulty. Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement .
Did you complete the replacement?		 - Go to Step 14  -
12
  1. Test for an intermittent or a poor electrical connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
  2. Repair as necessary.
Did you find and repair a condition?		 - Go to Step 14  Go to Step 13 
13 Replace the PCM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 14  -
14
  1. Use the scan tool in order to clear the DTCs.
  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.
Does the DTC run and pass?		 - Go to Step 15  Go to Step 2 
15 With a scan tool, observe the stored information, Capture Info.
Does the scan tool display any DTCs that you have not diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List - Vehicle System OK
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