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Home >> Chevrolet >> 2005 >> Venture LS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 3.4L DTC P0016 To P0138 >> DTC Tests >> DTC P0123 >> Test Description
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Test Description

The number below refers to the step number on the diagnostic table.

  1. 7:  This step allows the sensor to operate and permits access to the low reference circuit for the voltage drop measurement.
DTC P0123

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Engine Controls Connector End Views  or  Powertrain Control Module (PCM) Connector End Views 
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
  1. Start the engine.
  2. Monitor the DTC information with the scan tool.
Is DTC P0641 also set?		 - Go to DTC P0641 Go to Step 3 
3 Observe the throttle position (TP) sensor parameter with the scan tool.
Is the voltage more than the specified value?		 4.9 V Go to Step 5  Go to Step 4 
4
  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 5  Go to DTC P1121
5 Test for an intermittent and for a poor connection at the TP sensor. 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 13  Go to Step 6 
6
  1. Turn OFF the ignition.
  2. Disconnect the TP sensor electrical connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the TP sensor parameter with the scan tool.
Is the voltage less than the specified value?		 0.1 V Go to Step 7  Go to Step 8 
7 
  1. Turn OFF the ignition.
  2. Connect a jumper wire between each of the terminals in the TP sensor harness connector and the corresponding terminal at the TP sensor. Refer to Using Connector Test Adapters in Wiring Systems.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the low reference circuit of the TP sensor at the jumper wire terminal to a good ground with a DMM. Refer to Measuring Voltage Drop in Wiring Systems.
Is the voltage more than the specified value?		 0.2 V Go to Step 9  Go to Step 11 
8
IMPORTANT: Disconnecting the powertrain control module (PCM) may eliminate the short during testing.
Test the TP sensor signal circuit between the PCM and the TP sensor 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 13  Go to Step 12 
9 Test the low reference circuit between the PCM and the TP sensor for an open or for high resistance. Refer to Circuit Testing andWiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 10 
10 Test for an intermittent and for a poor connection at the PCM. 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 13  Go to Step 12 
11 Replace the TP sensor. Refer to Throttle Position (TP) Sensor Replacement .
Did you complete the replacement?		 - Go to Step 13  -
12 Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 13  -
13
  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 14 
14 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 in Vehicle DTC Information System OK
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