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Minimum Idle (Deville & Fleetwood) Chevrolet Corvette C4

Adjustments ~241 words
  1. Warm engine to normal operating temperature. Turn A/C and all accessories off. With key on and engine off, select Powertrain Control Module (PCM) override E.5.3., Idle Speed Control (ISC) motor. See ENTERING SELF-DIAGNOSTICS in appropriate G - TESTS W/ CODES article in this section.
  2. Press the WARMER button on Electronic Climate Control (EEC) panel. The fuel data center should alternately display E.5.3. and 99, indicating override function has started. The ISC will extend to maximum extend position.
  3. With ISC at maximum extension, Throttle Position Sensor (TPS) voltage should be 1.15-1.20 volts. If TPS voltage is less than 1.15 volts, go to next step. If TPS voltage is greater than 1.20 volts, go to step 5).
  4. Adjust ISC plunger out by turning plunger counterclockwise until TPS parameter reads 1.18 volts.
  5. Adjust ISC plunger in by turning plunger clockwise until TPS parameter reads 1.18 volts.
  6. Recheck ISC maximum extension setting. Press COOLER button to retract ISC plunger. Wait 5 seconds. Press the WARMER button and read TPS voltage. Adjust ISC plunger again if necessary.
  7. After all adjustments are made and while still in diagnostic mode, turn ignition off. Allow approximately 20 seconds for ISC motor to retract and perform a TPS learn routine.
  8. Re-enter diagnostics and repeat step 7). It takes 2 cycles for a successful TPS learn to occur. Remove alternator disable ground wire (Green harness connector plug). Start engine and check for proper ISC motor operation.

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