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Home >> Cadillac >> 1995 >> Eldorado Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Pcm Code Charts >> Code P056, Transaxle Input Speed Sensor Circuit Problem >> Failure Conditions
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Failure Conditions

PCM turns on MIL. PCM calculates transaxle input speed based on output speed and gear ratio of gear commanded. PCM calculates slip speed from calculated input speed and engine RPM. TCC engaged and garage shift adapts are maintained at current levels. Torque management is disabled.

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. With engine idling in Park or Neutral, PCM data PD72 should read 50-100 RPM less than engine RPM.
  2. Transaxle input speed sensor should generate a frequency of greater than zero Hertz with engine at idle. If frequency is not as specified, check circuits No. 1230 and 1231 and speed sensor for open or short inside transaxle.
  3. Checks circuits No. 1230 and 1231 for open or short to PCM. If circuit is okay, PCM is faulty.
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