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Home >> Saturn >> 1998 >> SL >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P0112 - IAT Sensor Circuit Temperature Out Of Range - Low >> Diagnostic Procedures

Diagnostic Procedures

  1. Turn ignition on. Using scan tool, monitor IAT sensor reading. If IAT sensor reading is less than -22°F (-30°C), go to next step. If IAT sensor reading is not less than -22°F (-30°C), problem is intermittent. See DIAGNOSTIC AIDS.
  2. Disconnect IAT sensor harness connector. Using a fused jumper wire, jumper IAT harness connector terminals. If IAT sensor reading is greater than 266°F (130°C), check for proper terminal connections. If connections are okay, replace IAT sensor. If IAT sensor reading is not greater than 266°F (130°C), go to next step.
  3. Remove jumper wire from IAT sensor connector terminals. Connect jumper between chassis ground and IAT sensor signal circuit at harness connector. If IAT sensor reading is greater than 266°F (130°C), go to next step. If IAT sensor reading is not greater than 266°F (130°C), go to step 5).
  4. Check IAT sensor ground circuit between IAT sensor and PCM. Repair as necessary. If circuit is okay, check for proper terminal connection. If connection is okay, replace PCM.
  5. Turn ignition off. Disconnect PCM harness connector. Check continuity of IAT sensor signal circuit. Repair as necessary. If circuit is okay, check for proper terminal connection. If connection is okay, replace PCM.
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