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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 P0301-P0306 >> Test Description

Test Description

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

The numbers below refer to the step numbers on the diagnostic table.

  1. 2:  DTCs that may cause a misfire DTC to set may include those for injector control circuits, oxygen sensors, the EVAP system, or fuel trim.
  2. 9:  This test is to determine if there is a problem in the heated oxygen sensor (HO2S) or wiring that is causing the ECM to alter the fuel trim. When the sensors are disconnected, the fuel system should go into Open Loop.
DTC P0301-P0306

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  Are any DTCs other than DTC P0300 or P0301-P0306 set? - Go to Diagnostic Trouble Code (DTC) List Go to Step 3 
3
  1. Start the engine.
  2. Allow the engine to idle or operate within the conditions listed in the Freeze Frame/Failure Records.
  3. Observe the Misfire Current Counter for this cylinder with a scan tool.
Is the Misfire Current Counter incrementing?		 - Go to Step 4  Go to Diagnostic Aids
4 Does the scan tool indicate that any HO2S voltage parameters are fixed above the specified value? 200 mV Go to DTC P0131, P0137, P0151, or P0157 Go to Step 5 
5 Does the scan tool indicate that any HO2S voltage parameters are fixed below the specified value? 900 mV Go to DTC P0132 or P0152 Go to Step 6 
6 Visually/physically inspect the following items:
  • The vacuum hoses for splits, kinks and proper connections
  • The throttle body and the intake manifold for vacuum leaks
  • The crankcase ventilation valve and/or system for vacuum leaks
  • Ensure that the ECM grounds are clean and secure.

Did you find and correct the condition?		 - Go to Step 10  Go to Step 7 
7
  1. Perform the injector balance test. Refer to Fuel Injector Balance Test with Special Tool and Fuel Injector Coil Test on the affected cylinder.
  2. Repair as necessary.
Did you find and correct the condition?		 - Go to Step 10  Go to Step 8 
8
  1. Perform the ignition system check. Refer to Electronic Ignition (EI) System Diagnosis .
  2. Repair as necessary.
Did you find and correct the condition?		 - Go to Step 10  Go to Step 9 
9 
  1. Turn OFF the ignition.
  2. Disconnect both HO2S 1 connectors.
  3. Start and idle the engine.
  4. Using the scan tool, monitor the Misfire Current Counter for this cylinder.
Is the Misfire Current Counter incrementing?		 - Go to Symptoms - Engine Mechanical in Engine Mechanical Go to DTC P0130, P0136, P0150, or P0156
10
  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 as specified in the supporting text.
Does the DTC run and pass?		 - Go to Step 11  Go to Step 2 
11 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 System OK
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