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Home >> Pontiac >> 2006 >> Vibe Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 1.8L (LV6) - DTC P0121 To DTC P0339 >> DTC P0138 >> Test Description

Test Description

The numbers below refer to the step numbers in 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 checks whether the malfunction is a high input condition.
  3. 3:  This step determines if the DTC P0138 is the result of a hard failure or an intermittent condition.
DTC P0138

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Powertrain Control Module (PCM) Connector End Views (FWD)  or  Powertrain Control Module (PCM) Connector End Views (AWD)  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 in Vehicle DTC Information
2 
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the HO2S 2 voltage with a scan tool.
Is the voltage more than the specified value?		 1050 mV Go to Step 4  Go to Step 3 
3 
  1. Perform the scan tool Clear DTC Information function.
  2. Place the vehicle into Check mode, using the scan tool. Refer to Service Bay Test .
  3. Operate the vehicle within the Freeze Frame conditions, as noted.
Does DTC P0138 set?		 - Go to Step 4  Go to Diagnostic Aids
4
  1. Disconnect the heated oxygen sensor (HO2S) 2 electrical connector located behind the front floor console. Refer to Heated Oxygen Sensor Replacement - Position 2 (FWD) or Heated Oxygen Sensor Replacement - Position 2 (AWD) .
  2. Turn ON the ignition, with the engine OFF.
Is the voltage within the specified value?		 35-55 mV Go to Step 6  Go to Step 5 
5
  1. Test for a short to voltage in the HO2S 2 input circuit. Refer to Circuit Testing in Wiring Systems.
  2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 8  Go to Step 7 
6 Replace the HO2S 2. Refer to Heated Oxygen Sensor Replacement - Position 2 (FWD) or Heated Oxygen Sensor Replacement - Position 2 (AWD) .
Did you complete the replacement?		 - Go to Step 8  -
7 Replace the powertrain control module (PCM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 8  -
8
  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 9  Go to Step 2 
9 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 in Vehicle DTC Information System OK
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