2010 Cadillac Truck Escalade ESV AWD V8-6.2L Page 1947
lamp (MIL) when one of the following occur:
* The ECM detects the same fuel trim failure during 2 consecutive trips.
* The ECM detects any fuel trim failure during any subsequent trip if the conditions at the time of failure meet the following criteria:
- The engine load is within 20 % of the previous test that failed.
- The engine speed is within 375 RPM of the previous test that failed.
- The engine coolant temperature is in the same range of the previous test that failed.
Conditions for Clearing the MIL/DTC
* The ECM turns OFF the malfunction indicator lamp (MIL) at the beginning of the fourth ignition cycle, after 3 ignition cycles that the
diagnostic runs and does not fail.
* A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
* A history DTC and related Freeze Frame data clears after 40 warm-up cycles, if no failures are reported by this or any other emission related
diagnostic.
* Clear the MIL and the DTC with a scan tool.
Reference Information
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
* Disregard any transmission symptoms, antilock brake system (ABS) indicators, and traction control system (TCS) indicators until any fuel
trim faults are repaired. A fuel trim fault may cause default actions such as harsh shifts and illumination of the ABS/TCS indicators.
* E85 compatible engine only-Over estimation of the ethanol content will result in a rich shift of fuel trim values, and under-estimation will
result in a lean shift of fuel trim values. A fuel trim DTC may set if the learned alcohol content, Fuel Alcohol Content parameter on the scan
tool, is different than the measured alcohol content in the vehicle such that fuel trim values exceed failure threshold values. Refer to Fuel
Composition Diagnosis (See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component Tests and
General Diagnostics).
* Verify that other DTCs are not set.
锟斤拷If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code Descriptions/Diagnostic
Trouble Code (DTC) List - Vehicle).
* Allow the engine to reach operating temperature. With the engine running, observe the HO2S parameter with a scan tool. The HO2S value
should vary from approximately 40 mV to approximately 900 mV, and respond to fueling changes.
锟斤拷If the value does not vary from approximately 40 mV to approximately 900 mV, refer to DTC P0131, P0132, P0137, P0138, P0151,
P0152, P0157, or P0158 (See: P Code Charts/P0131), DTC P0133, P013A-P013F, P014A, P014B, P0153, P1133, or P1153 ( See: P
Code Charts/P0133) or DTC P0134, P0140, P0154, or P0160 (See: P Code Charts/P0134).
Note: EVAP purge enablement may cause the FT to be momentarily outside the normal range.
* The normal Short Term FT parameter should be between +10 % and -10 %, with near 0 % the optimum, with the engine running at operating
temperature.
* The Long Term FT parameter should be between +10 % and -10 %, with near 0 % the optimum, with the engine running at operating
temperature.
* Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the
conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
P0171 or P0174
Allow the engine to reach operating temperature. With the engine running, observe the affected Long Term FT parameter with a scan tool. The
reading should be between 0-19 %.
