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Home >> Oldsmobile >> 1990 >> Cutlass Calais Base, 4D Sedan, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 3.3L PFI >> Diagnostic Tests >> Code 21: TPS Signal Volt High >> Notes

Code 21: TPS Signal Volt High: Notes

  1. A Code 21 will set if engine is running and the following conditions occur:
    • TPS signal voltage is greater than 4.9 volts at any time.

    or if:

    • Mass Airflow Sensor (MAF) signal is low.
    • Throttle Position Sensor (TPS) signal voltage is greater than 1.5-2.5 volts.
    • Code 34 is not present.
    • Both conditions must be met for 5 seconds.

    With closed throttle, ignition on or engine at idle, voltage should be less than .33-.46 volt. If voltage is not okay, check TPS adjustment. See ADJUSTMENTS article in this section.

  2. With the TPS sensor disconnected, Code 22 should set and TPS voltage should go low if the ECM and wiring are okay.
  3. Probing circuit No. 452 with a test light checks the sensor ground circuit. A faulty sensor ground circuit will cause a Code 21.
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