2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 1849
1. Install any components or connectors that have been removed or replaced during diagnosis.
2. Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced.
3. Turn ON the ignition, with the engine OFF.
Important: DO NOT clear codes with the engine running. The codes may reset in the same ignition cycle.
4. Clear the DTCs.
5. Turn OFF the ignition for 60 s.
6. Start the engine.
7. Duplicate the Conditions for Running the DTC and use the Freeze Frame/Failure Records, if applicable, in order to verify the DTC does not
reset. If the DTC resets, or another DTC is present, refer to the Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble
Code Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle) and perform the appropriate diagnostic procedure.
P0174
DTC P0171, P0172, P0174, or P0175
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0171
- Fuel Trim System Lean Bank 1
DTC P0172
- Fuel Trim System Rich Bank 1
DTC P0174
- Fuel Trim System Lean Bank 2
DTC P0175
- Fuel Trim System Rich Bank 2
Circuit/System Description
The engine control module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel
economy, and emission control. Fuel delivery is controlled differently during Open Loop and Closed Loop (CL). During Open Loop, the ECM
determines fuel delivery based on sensor signals without heated oxygen sensor (HO2S) input. During CL, the ECM adds HO2S inputs and level of
purge to calculate the short and long term fuel trim (FT) adjustments. If the HO2S indicates a lean condition, the fuel trim values will be above 0 %.
If the HO2S indicates a rich condition, the FT values will be below 0 %. The short term FT values change rapidly in response to the HO2S voltage
signals. The long term FT makes coarse adjustments in order to maintain an optimum air/fuel ratio. A block of cells contain information arranged in
combinations of engine RPM and engine load for a full range of vehicle operating conditions. The long term FT diagnostic is based on an average
of cells currently being used. The ECM selects the cells based on the engine speed and load. The FT diagnostic will conduct a test to determine if a
rich failure actually exists or if excessive vapor from the evaporative emission (EVAP) canister is causing a rich condition.
If the ECM detects an excessively lean condition, DTC P0171 or P0174 sets. If the ECM detects an excessively rich condition, DTC P0172 or
P0175 sets.
Conditions for Running the DTC
* DTCs P0030, P0036, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0117, P0118, P0120, P0121, P0128, P0130, P0131, P0132,
P0133, P0134, P0135, P0136, P0137, P0138, P0140, P0141, P0201-P0208, P0220, P0300, P0301-P0304, P0442, P0443, P0446, P0449,
P0452, P0453, P0455, P0496, P1106, P1107, P1114, P1115, P1133, P1516, P2101, P2119, P2120, P2125, P2135, P2138, P2176 are not set.
* The engine is in Closed Loop status.
* The engine coolant temperature (ECT) is between -40 and +150掳C (-40 and +302掳F).
* The intake air temperature (IAT) is between -20 and +150掳C (-4 and +302掳F).
* The manifold absolute pressure (MAP) is between 10-255 kPa (1.45-37 psi).
* The vehicle speed is less than 134 km/h (83 mph).
* The engine speed is between 375-7,000 RPM.
* The mass air flow (MAF) is between 1-510 g/s.
* The barometric pressure (BARO) is more than 70 kPa (10.2 psi).
* The fuel level is more than 10 %.
