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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1332 (Engine Controls Diagnostic (DTC P0068 To DTC P0174) -- 5.7L) >> Diagnosis >> DTC P0131 or P0151 >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 2:  If the voltage is varying above and below the specified range, the condition is not present.
DTC P0131 or P0151

Step Action Value(s) 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-Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2 
  1. Start the engine.
  2. Allow the engine to reach operating temperature. Refer to Scan Tool Data List .
  3. Observe the affected heated oxygen sensor (HO2S) voltage parameter with a scan tool.
Is the HO2S voltage parameter varying above and below the specified range?		 300-600 mV Go to Step 3  Go to Step 4 
3
  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 4  Go to Intermittent Conditions
4
  1. Turn OFF the ignition.
  2. Disconnect the affected heated oxygen sensor (HO2S).
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the HO2S voltage parameter with a scan tool.
Is the HO2S voltage parameter less than the specified value?		 100 mV Go to Step 6  Go to Step 5 
5
  1. Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S harness connector on the engine harness side and a good ground.
  2. Observe the HO2S voltage parameter with a scan tool.
Is the HO2S voltage parameter less than the specified value?		 100 mV Go to Step 7  Go to Step 8 
6 Test the HO2S high signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 9 
7 Test the HO2S low signal circuit for a short to the HO2S heater low control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 10 
8 Test the HO2S high signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 12 
9 Test the HO2S high signal circuit for a short to the following circuits:
  • HO2S low signal circuit
  • HO2S heater low control circuit

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 12 
10
  1. The HO2S may be detecting a lean exhaust condition or may be contaminated. Inspect for the following conditions:
  2. Repair any of the above or similar engine conditions as necessary.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 11 
11 Test for shorted terminals and for poor connections at the HO2S. 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 15  Go to Step 13 
12 Test for shorted terminals and for poor connections at the powertrain control module (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 15  Go to Step 14 
13 Replace the affected HO2S. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 1 or Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 1 .
Did you complete the replacement?		 - Go to Step 15  -
14 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 - Go to Step 15  -
15
  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 16 
16 Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?		 - Go to Diagnostic Trouble Code (DTC) List System OK
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