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.

2: This step determines whether the fault is present.
4: If DTC P2178 and DTC P2180 set at the same time, then both banks of the engine are operating rich. Inspect items that would cause both banks of the engine to operate rich.
5: Disconnecting the mass air flow (MAF) sensor determines if the MAF sensor signal is skewed. If the Short Term FT parameter changes more than the specified value, there is a condition with the MAF sensor. A MAF sensor condition can cause this DTC without setting a MAF DTC. If there is a MAF sensor condition, the MAF sensor parameters will appear to be within range.

DTC P2178 or P2180

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, except P2178 and P2180, refer to those DTCs before proceeding with this diagnostic. Idle the engine at the normal operating temperature. The fuel system is in Closed Loop. Observe the Total Fuel Trim Avg. parameter for bank 1 or bank 2 with a scan tool. Is the Total Fuel Trim Avg. less than the specified value?	-22%	Go to Step 3	Go to Step 4
3	Observe the Freeze Frame and/or the Failure records data for this DTC. Turn the ignition OFF for 30 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. Does the DTC fail this ignition cycle?	-	Go to Step 4	Go to Diagnostic Aids
4	Are both banks of the engine operating rich?	-	Go to Step 5	Go to Step 7
5	Start the engine. IMPORTANT: Additional DTCs set with the mass air flow (MAF) sensor disconnected. Disconnect the MAF sensor harness connector while the engine is operating. Observe the Short Term FT parameter for bank 1 and bank 2 with a scan tool. Connect the MAF sensor after completing this step. Does the Short Term FT parameter for both banks of the engine change more than the specified value with the MAF sensor disconnected?	20%	Go to DTC P0101	Go to Step 6
6	Inspect for the following conditions: Inspect for a collapsed air intake duct. Inspect for a restricted air filter element. Refer to Air Cleaner Element Replacement . Inspect the MAF sensor for foreign objects. Refer to Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement . Inspect for excessive fuel in the crankcase. Change the oil as necessary. Inspect for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis (w/o Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (w/Special Tool) . 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 in Engine Mechanical - 3.6L (LY7). Did you find and correct the condition?	-	Go to Step 8	Go to Fuel System Diagnosis
7	Inspect for the following conditions: Inspect for rich injectors. Refer to Fuel Injector Coil Test Inspect for restricted exhaust system. Refer to Symptoms - Engine Exhaust in Engine Exhaust. Inspect for an engine mechanical condition. Refer to Symptoms - Engine Mechanical in Engine Mechanical - 3.6L (LY7). Did you find and correct the condition?	-	Go to Step 8	Go to Diagnostic Aids
8	Turn OFF the ignition for 30 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 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