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Home >> Cadillac >> 2000 >> Seville STS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Self-Diagnostics - 4.6L >> Diagnostic Tests >> DTC P1258: Engine Coolant OVERTEMPERATURE Protection Mode Active >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . After performing OBD system check, go to next step.
  2. Using scan tool, check if DTC P0118, P0480 or P0481 is set. If any of these DTC(s) are present, diagnose affected DTC(s). If these DTC(s) are not present, go to next step.
  3. Check if cooling fans are operating properly. If cooling fans are operating properly, diagnose cooling system. If cooling fans are not operating properly, diagnose cooling fans.
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