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Home >> Chevrolet >> 2005 >> Malibu Maxx >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 5 (Engine Control System - 2.2L (L61) - DTC P0137 To DTC P0446) >> Diagnosis >> DTC P0172 >> Test Description

Test Description

WARNING: This page is about a different variant/trim than selected.

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

  1. 8:  If conditions were not corrected, a worn cam, worn intake or exhaust valves or other engine mechanical failure may be at fault.
DTC P0172

Step Action Values Yes No
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2 Are any DTCs other than DTC P0172 also set? - Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information Go to Step 3 
3
  1. Install a scan tool.
  2. Review the Freeze Frame/Failure Records and record the displayed data for this DTC.
  3. Select Fuel Trim Data parameter.
  4. Start the engine and observe the Long Term FT parameter with a scan tool.
Is the Long Term FT parameter less than the specified value?		 -46% Go to Step 4  Go to Diagnostic Aids
4
  1. Start the engine.
  2. Allow the engine to reach operating temperature.
  3. Put the transmission in PARK or NEUTRAL position.
  4. Turn off all of the accessories.
  5. Allow the engine to idle.
  6. Observe the Manifold Absolute Pressure (MAP) sensor parameter with a scan tool.
Is the MAP sensor parameter within the specified range?		 19-42 kPa Go to Step 5  Go to DTC P0106
5
  1. Operate the engine at idle.
  2. Observe the heated oxygen sensor (HO2S) parameters with a scan tool.
Does the scan tool indicate that the values are within the specified range and fluctuating?		 200-800 mV Go to Step 6  Go to Step 7 
6
  1. Turn OFF the engine.
  2. Visually and physically inspect the following items:
    • The vacuum hoses for splits, kinks, and proper connections-Refer to Emission Hose Routing Diagram .
    • The air intake duct for being collapsed or restricted
    • The air filter for being dirty or restricted
    • For objects blocking throttle body
Did you find and correct the condition?		 - Go to Step 9  Go to Step 8 
7
  1. Turn OFF the engine.
  2. Inspect for the following conditions:
    • The HO2S for proper installation
    • Ensure that the electrical connectors and wires are secured and not contacting the exhaust system.
    • The HO2S signal circuit 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 9  Go to Fuel System Diagnosis
8  Inspect for the following:
Did you find and correct the condition?		 - Go to Step 9  Go to Symptoms - Engine Mechanical in Engine Mechanical
9
IMPORTANT: After repairs, use the scan tool Fuel Trim Reset function in order to reset the Long Term Fuel Trim.
  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 10 
10 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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