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Home >> Cadillac >> 2007 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 28 (Engine Control System - Self-Diagnostics) >> Diagnostic Tests >> DTC P0171: Fuel Trim System Lean >> Test Description
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Test Description

WARNING: This page is about a different car, the 2003 Pontiac Vibe. 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 procedures.

  1. 1  - The Diagnostic System Check - Engine Controls prompts the technician to complete some basic checks and store freeze frame data, if applicable. This creates an electronic copy of data taken when fault occurred. The information is then stored in the scan tool for later reference.
  2. 3  - Visually and physically checking items that may cause a lean condition that may determine the reason the DTC set.
  3. 4  - Engine control sensors that are found to be out range (skewed) or fixed, can cause the engine to run lean. Go to the applicable sensor DTC diagnostic procedure for direction in diagnosing any possible sensor error. See DIAGNOSTIC TROUBLE CODE DEFINITIONS 
  4. 6  - Contaminants in the fuel, such as alcohol or water, can create a lean condition and set DTC P0171.
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