1988 Chevrolet Spectrum ExpressFACTORY OEM SERVICE PROCEDURE

Code 13, 44 & 45 (O2)

  1. Jumper ALDL. With engine at normal operating temperature, above 158°F (70°C), run engine at 2000 RPM for 2 minutes. If check engine light is flashing closed loop (light flashes once per second), go to step 4).
  2. If check engine light is flashing open loop (light flashes 25 times per second), turn engine off. Disconnect O2 sensor harness and ground Yellow wire. Start engine and note check engine light. Light should flash open loop for about 2 minutes then go out. If light goes out in 2 minutes, replace O2 sensor.
  3. If light stays on, check continuity in O2 sensor harness. Check that continuity exists between ECM harness connector B23 and Yellow connector wire at O2 sensor, and between B22 and ground. If harness checks bad, repair or replace. If harness checks good, replace ECM.
  4. If check engine light is flashing closed loop, remove ALDL jumper wire and clear code. Run engine above 2000 RPM for one minute. Note check engine light.
  5. If check engine light is on, turn engine off. Jumper ALDL and turn ignition on. Note code and refer to applicable code diagnosis. If check engine light is off, problem may be intermittent.
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When to See a Mechanic

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

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

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