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Home >> Cadillac >> 2004 >> CTS Base, 3.6 7 >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 13 (Engine Controls - 2.6L & 3.2L - Diagnosis (DTC P0172 - P0446)) >> Diagnostic Trouble Codes >> DTC P0172 or P0175 >> Diagnostic Aids

Diagnostic Aids

WARNING: This page is about a different variant/trim than selected.
DTC P0172 or P0175

Step Action Values Yes No
1 Did you perform the Diagnostic System Check-Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2
IMPORTANT: If any DTCs are set, other than P0172 or P0175, refer to those DTCs before continuing.
  1. Install a scan tool.
  2. Start the engine.
  3. Operate the vehicle within the Conditions for Running the DTC.
  4. Record the LT FT Cruise/Acce and LT FT Idle/Decel. parameter values.
  5. Turn OFF the engine.
  6. Turn ON ignition, with engine OFF.
  7. Review the Freeze Frame/Failure Records and record displayed data for this DTC.
Does the scan tool indicate that the LT FT Cruise/Acce. parameter is less than the specified value?		 -23% Go to Step 4  Go to Step 3 
3 Does the scan tool indicate that the LT FT Idle/Decel. parameter is less than the specified value? -8.5% Go to Step 4  Go to Diagnostic Aids
4
  1. Operate 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 5  Go to Step 6 
5
  1. Turn OFF engine.
  2. Visually and physically inspect the following items:
    • The inlet screen of the mass air flow (MAF) sensor for blockage
    • 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
    • Inspect for objects blocking throttle body
Did you find and correct the condition?		 - Go to Step 8  Go to Step 7 
6
  1. Turn OFF the engine.
  2. Inspect the HO2S for proper installation.
  3. Verify that the electrical connectors and wires are secured and are not contacting the exhaust system.
Did you find and correct the condition?		 - Go to Step 8  Go to Fuel System Diagnosis
7
  1. Inspect for the following conditions:
    • Excessive fuel in the crankcase
    • The evaporative emissions (EVAP) control system.
    • The fuel pressure regulator for proper operation-Refer to Fuel System Diagnosis .
  2. Perform the Fuel Injector Balance Test.
Did you find and correct the condition?		 - Go to Step 8  Go to Symptoms - Engine Mechanical in Engine Mechanical
8
IMPORTANT: After repairs, use the scan tool Fuel Trim Reset function in order to reset the Long Term Fuel.
  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 9 
9 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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