Test Description

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

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

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: This step determines whether a condition exists.
4: If DTC P0172 and P0175 are set at the same time, this indicates both banks of the engine are operating rich. Inspect the items that would cause both banks to operate rich.
6: This step tests for excess fuel from a fuel injector. The fault may be a fuel injector or the fuel injector electrical circuit.

DTC P0172 or P0175

Step	Action	Value(s)	Yes	No
1	Did you perform the Diagnostic System Check - Vehicle?	-	Go to Step 2	Go to Diagnostic System Check - Vehicle
2	IMPORTANT: If any DTCs are set, except P0172 and P0175, refer to those DTCs before proceeding with this diagnostic. Start the engine. Idle the engine at the normal operating temperature. Operate the vehicle until the scan tool indicates Closed Loop. Observe the Long Term FT parameter for bank 1 or bank 2 with a scan tool. Does the scan tool display more than the specified value?	-16%	Go to Step 3	Go to Step 4
3	Turn the ignition ON, with the engine OFF. Observe the Freeze Frame and/or the Failure records data for this DTC. Clear the DTCs with a scan tool. Turn the ignition OFF for 90 seconds. Start the engine. 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 and/or the Failure records data. Did the DTC fail this ignition?	-	Go to Step 4	Go to Diagnostic Aids In This Test
4	Are both banks of the engine operating rich?	-	Go to Step 5	Go to Step 6
5	Visually and physically inspect for any of the following conditions: Inspect for a collapsed air intake duct. Inspect for a restricted air filter element. Refer to Air Cleaner Element Replacement . Inspect for excessive fuel in the crankcase. Change the oil as necessary. Test the fuel system for operating rich. Refer to Fuel System Diagnosis . Inspect for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis . Inspect the evaporative emission (EVAP) control system for the correct operation. Refer to Evaporative Emission Control System Description . Inspect the exhaust gas recirculation (EGR) value for the correct operation. Refer to Exhaust Gas Recirculation (EGR) System Description . Inspect the engine control grounds for being clean, tight, and in the correct locations. Inspect for an engine mechanical condition. Refer to Symptoms - Engine Mechanical . Did you find and correct the condition?	-	Go to Step 9	Go to Step 7
6	Visually and physically inspect for any of the following conditions: Verify that the discharge of fuel is regular and even. Refer to Fuel Injector Balance Test with Tech 2 or Fuel Injector Balance Test with Special Tool . Verify that the electrical resistance of the injector coils are all within specifications. Refer to Fuel Injector Solenoid Coil Test . Inspect for a restricted exhaust. Refer to Restricted Exhaust . Inspect for an engine mechanical condition. Refer to Symptoms - Engine Mechanical . Did you find and correct the condition?	-	Go to Step 9	Go to Step 7
7	Test for an intermittent and for a poor connection at the appropriate heated oxygen sensor (HO2S). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?	-	Go to Step 9	Go to Step 8
8	Replace the HO2S. Refer to the appropriate procedure: Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 Did you complete the replacement?	-	Go to Step 9	-
9	Clear the DTCs with a scan tool. Turn OFF the ignition for 90 seconds. Start the engine. Reset the fuel trim system with a scan tool. 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	In order to ensure that the performance of the catalyst has not been affected by the fault that set this DTC, operate the vehicle within the conditions for running and setting DTC P0420/0430 and verify that DTC P0420/0430 runs and passes. Refer to DTC P0420 or P0430 . Does the DTC run and pass?	-	Go to Step 11	Go to DTC P0420 or P0430
11	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	System OK