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Home › Cadillac › 1998 › Seville STS › Repair and Diagnosis › Body & Frame › Body, Cab Control Systems › Body Control Module › Diagnosis & Testing › DTC B1317: In-Car Air Temperature Sensor › Diagnostic Procedures

Diagnostic Procedures

  1. Perform BCM diagnostic system check. See BCM DIAGNOSTIC SYSTEM CHECK  . After performing system check, go to next step.
  2. Turn ignition off. Disconnect in-car air temperature sensor harness connector (located behind dash, left of steering column). Turn ignition on. Check voltage between sensor harness connector terminals "A" (Dark Green wire) and "B" (Brown wire). See WIRING DIAGRAMS  . If voltage reading is 5 volts, go to next step. If voltage reading is not 5 volts, go to step 6).
  3. Turn ignition off. Reconnect sensor harness connector. Turn ignition on. Clear DTCs using scan tool. Cycle ignition on and off several times. If DTC resets, go to next step. If DTC does not reset, problem is intermittent. Check for intermittent or poor connections.
  4. Replace IPM. After replacing IPM, go to step 12).
  5. Replace sensor. After replacing sensor, go to step 12).
  6. Check voltage between ground and sensor terminal "A" (Light Green/Black wire). If voltage reading is 5 volts, go to next step. If voltage reading is not 5 volts, go to step 9).
  7. Check if HVAC related DTCs are set. If HVAC DTCs are set, go to next step. If no HVAC DTCs are set, go to step 11).
  8. Check for open in Yellow wire between sensor terminal "B" and IPM connector terminal B8. If circuit is open, repair as necessary. After repairs, go to step 12).
  9. Check voltage between ground and IPM harness connector terminal B4 (Dark Green wire). If voltage reading is 5 volts, go to next step. If voltage reading is not 5 volts, go to step 4).
  10. Repair open in Dark Green wire between IPM connector terminal B4 and sensor. After repairs, go to step 12).
  11. Repair open in Yellow wire between IPM connector terminal B8 and sensor terminal "D". After repairs, go to next step.
  12. Clear DTCs. Recheck for proper A/C system operation. Use scan tool to perform INSTANT INSIDE TEMPERATURE SENSOR UPDATE.
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