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Home >> Cadillac >> 2009 >> STS Base, 4.6 A, AWD >> Repair and Diagnosis >> Steering >> Power Steering System >> Diagnostic Information and Procedures >> DTC C056D >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the X2 harness connector at the PSCM.
  2. Ignition OFF, test for less than 5 ohms between the ground circuit terminal 1 and ground.
    • If greater than specified value, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 6 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Ignition OFF, reconnect the X2 harness connector. Disconnect the X3 harness connector at the PSCM.
  5. Ignition OFF, test for less than 5 ohms between the ground circuit terminal 3 and ground.
    • If greater than specified value, test the ground circuit for an open/high resistance.
  6. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 1 and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  7. Test for B+ on the control circuit terminal 10.
    • I less than specified value, test the control circuit for an short to ground or an open/high resistance.
  8. Ignition OFF, reconnect the X3 harness connector. Disconnect the X1 harness connector at the PSCM.
  9. Test for less than 5 ohms between the signal circuit terminal 7 and the signal circuit terminal 8.
    • If greater than specified value, test both signal circuits for an open/high resistance. If the circuits test normal, test or replace the upper intermediate steering shaft.
  10. Test for less than 5 ohms between the signal circuit terminal 7 and the signal circuit terminal 14.
    • If greater than specified value, test both signal circuits for an open/high resistance. If the circuits test normal, test or replace the upper intermediate steering shaft.
  11. Test for less than 5 ohms between the signal circuit terminal 8 and the signal circuit terminal 14.
    • If greater than specified value, test both signal circuits for an open/high resistance. If the circuits test normal, test or replace the upper intermediate steering shaft.
  12. If all circuits test normal, replace the PSCM. If the DTC resets, replace the upper intermediate steering shaft.
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