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Corolla & Tercel

  1. Ensure coolant temperature is less than 45°F (7°C). Disconnect vacuum hose from vacuum switch. On Corolla and Tercel (Calif. models), disconnect main vacuum hose going to both vacuum switches. Where appropriate, see Figure, Figure, Figure or Figure on Corolla models and see Figure or Figure on Tercel models.
  2. Start engine and set idle. Check that vacuum is not felt from disconnected vacuum hose. Reconnect vacuum hose to vacuum switch.
  3. Start engine and warm to operating temperature. Check Electronic Bleed Air Control Valve (EBCV) operation. Disconnect EBCV connector. Where appropriate, see Figure, Figure, Figure or Figure on Corolla models and see Figure or Figure on Tercel models. Increase engine speed to 2500 RPM and reconnect EBCV connector. Engine speed should momentarily drop approximately 300 RPM.
  4. Reduce engine speed to idle. Disconnect EBCV connector and then reconnect. Engine speed should not change. Disconnect vacuum hose from vacuum switch.
  5. Disconnect EBCV connector. Increase engine speed to 2500 RPM. Reconnect EBCV connector. Check that engine speed does not change.
  6. If carburetor feedback system does not function as described, test individual system components.
  7. On Corolla, check vacuum switch, throttle position switch, oxygen sensor, RPM signal ("Ne" terminal on ignitor), thermostatic vacuum switching valve and electronic air bleed control valve. Also check Emission Control Computer wiring and ground connection.
  8. On Tercel, check vacuum switch, oxygen sensor, bi-metallic vacuum switching valve, throttle position switch, RPM signal ("Ne" terminal on ignitor), electronic bleed air control valve and vacuum transmitting valve. Also check Emission Control Computer wiring and ground connection.
NOTE: On Pickup (22R Calif.), Air Suction and Carburetor Feedback system are controlled by Emission Control Computer and functions as a complete system.
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