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Home >> Cadillac >> 1996 >> Seville SLS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P0120 - TP Sensor System Performance >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. After performing OBD system check, go to next step.
  2. Turn ignition on. Using scan tool, check if DTC P0300 is also present. If DTC P0300 is present, diagnose DTC P0300 first. If DTC P0300 is not present, go to next step.
  3. If DTC P0121 or P0122 is present, diagnose affected DTC first. If DTCs are not present, go to next step.
  4. Using scan tool, select FAILURE REC. under DTC mode. Note TP sensor display. If snapshot TP sensor reading is zero degrees or less, go to next step. If snapshot TP sensor reading is greater than zero degrees, go to step 8).
  5. An intermittent low voltage reading occurred on the TP sensor circuit. Check for possible open or short to ground in TP sensor signal circuit or open in 5-volt reference circuit. Repair as necessary. If circuits are okay, go to next step.
  6. Slowly depress accelerator from closed throttle to wide open throttle. Note TP sensor reading. Watch for a sudden skip or jump in TP sensor reading. If reading skips or jumps, go to next step. If reading does not skip or jump, fault is not present.
  7. Check for binding or sticky throttle. Check for chaffed TP sensor wires. Repair as necessary. If repairs were not necessary, go to step 11).
  8. If snapshot TP sensor reading is greater than 85 degrees, go to next step. If the snapshot of TP sensor reading is less than 85 degrees, go to step 6).
  9. An intermittent high voltage reading occurred on the TP sensor circuit. Check for open in TP sensor ground circuit or short in TP sensor signal circuit. Repair as necessary. If circuits are okay, go to next step.
  10. Slowly depress accelerator from closed throttle to wide open throttle. Note TP sensor reading. Watch for a sudden skip or jump in TP sensor reading. If reading skips or jumps, go to next step. If reading does not skip or jump, fault is not present.
  11. Replace TP sensor.
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