1988 Chevrolet Spectrum ExpressFACTORY OEM SERVICE PROCEDURE

Code 22 (TPS)

  1. Clear codes. Start engine and idle for one minute or until check engine light comes on. If light will not come on, problem is intermittent.
  2. If check engine light comes on, turn off engine. Jumper ALDL and turn ignition on. Note codes. If code 22 is present, turn off engine. Clear code and remove ALDL jumper.
  3. Disconnect TPS connector and jumper between Red and Light Green/Red wire connectors. Start engine and idle for one minute or until light comes on. Turn engine off. Jumper ALDL and turn ignition on. Note code.
  4. If code 21 is present, remove jumper wire and connect harness. Adjust TPS to proper specification. If TPS cannot be adjusted, replace TPS.
  5. If code 22 is present, remove jumper wire. Using a digital voltmeter, check voltage between Green and Light Green/Red wire terminals at TPS connector. With ignition on, reading should be 4-6 volts.
  6. If reading is above 6 volts, check TPS harness Red wire connector to ECM connector B13 for short or ground, faulty connection or bad ECM.
  7. If reading is below 4 volts, repeat step 6) for Light Green/Red harness connector and B14.
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:

  • • 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.