1989 Geo Spectrum 2D Hatchback, AutomaticFACTORY OEM SERVICE PROCEDURE

Diagnostic Aids

Check for corrosion at ECM connectors and terminals. Check for windshield or heater core leaks. If leaks are present, repair leak, clean connector terminals and check for Code 55 again. If Code 55 sets again, replace ECM.

Fig 1: Code 55, Circuit Wiring Diagram & Flow Chart
G121678Courtesy 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.