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Home >> Cadillac >> 1998 >> Eldorado Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P0111 - IAT Sensor Circuit Performance >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK , then go to next step.
  2. If DTC P0112 or P0113 is also present, diagnose affected DTC(s) first. If other DTCs are not present, go to next step.
  3. Turn ignition on, engine off. Using scan tool, select FAILURE RECORD in DTC mode and note IAT snapshot display. If snapshot reading is less than -29°F (-34°C), go to next step. If snapshot reading is not -29°F (-34°C), go to step 5).
  4. An intermittent high resistance reading occurred on IAT sensor circuit. Check for open in IAT ground circuit and IAT signal circuit. Repair as necessary. If circuits are okay, go to step 7).
  5. If snapshot IAT sensor reading is greater than 291°F (144°C), go to next step. If reading is not greater than 291°F (144°C), go to step 7).
  6. An intermittent low resistance reading occurred in the IAT sensor circuit. Check for possible short to ground in IAT sensor signal circuit. Repair as necessary. If circuit is okay, go to next step.
  7. Artificially raise IAT temperature, from cool to warm. As IAT sensor warms, watch IAT sensor reading on scan tool. Look for a skip or jump in the value. If a skip or jump is noted, go to next step. If value did not skip or jump, see DIAGNOSTIC AIDS.
  8. Replace IAT sensor.
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