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Home >> Chevrolet >> 2003 >> Tracker 2D Utility, RWD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 2.0L >> Diagnostic Tests >> DTC P0121: Throttle Position Sensor Performance >> Test Description
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Test Description

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 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. 4 -  This step checks whether the malfunction that caused the DTC P0121 is still present. Driving the vehicle under these conditions will verify whether the fault is present. After performing the scan tool clear DTC information function, the DTC P0121 diagnostic can be monitored on the scan tool under the Not Ran Since Code Cleared selection in the DTC Information menu. If a DTC P0121 appears in the Not Ran Since Code Cleared list, the P0121 diagnostic has not yet run. When the DTC P0121 does not appear in the Not Ran Since Code Cleared list, the P0121 diagnostic has run. If the MIL is NOT illuminated, and there is no Pending DTC Status in DTC Information, the P0121 diagnostic has passed. The DTCs MUST be cleared in order to view the Current Status of the Not Ran Since Code Cleared list. DO NOT forget that the Not Ran Since Code Cleared list only indicates that the test has run, not whether the test passed or failed. The DTC Information screen must be checked for Current or Pending status, in order to determine the outcome of the diagnostic test involved.
  3. 7 -  This step inspects the TP sensor performance. If there are any breaks, dips, or fixed values observed in the resistance readings while opening and closing the throttle, the TP sensor is faulty.
  4. 11 -  Clearing the DTCs by removing the DOME fuse also clears the PCM long term memory. Using the scan tool to clear DTCs leaves the long term memory active. DTC emitting diagnostics may not run to completion as expected unless the long term memory is cleared. Removal of the DOME fuse also clears the time display of the radio. The DTC P0121 diagnostic can be monitored on the scan tool under the Not Ran Since Code Cleared selection in the DTC Information menu. If a DTC P0121 appears in the Not Ran Since Code Cleared list, the DTC P0121 diagnostic has not yet run. When the DTC P0121 does not appear in the Not Ran Since Code Cleared list, the DTC P0121 diagnostic has run. If the MIL is NOT illuminated, and there is no Pending DTC Status in DTC Information, the DTC P0121 diagnostic has passed. The DTCs MUST be cleared in order to view the Current Status of the Not Ran Since Code Cleared list. DO NOT forget that the Not Ran Since Code Cleared list only indicates that the test has run, not whether the test passed or failed. The DTC Information screen must be checked for Current or Pending status, in order to determine the outcome of the diagnostic test involved.
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