1993 Cadillac AllanteFACTORY OEM SERVICE PROCEDURE

Notes On Fault Tree

NOTE: Numbers in list refer to circled numbers in diagnostic flow chart.
  1. CKT 424 is the BYPASS circuit and should be low at key ON.
  2. CKT 423 is the IGNITION CONTROL circuit and should be low with the ICM not receiving crankshaft position sensor pulses.
  3. CKT 424, BYPASS circuit, should be high with engine running.
Fig 1: Ignition Control Check Flow Chart
G00060928Courtesy of GENERAL MOTORS CORP.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.