P1289 Buick Air Fuel Ratio Sensor 1 Circuit Slow Response Bank 2

P1290 Buick Cylinder Head Temperature Sensor Signal Less Than Self-Test Range

Possible causes
  • Grounded circuit in CHT harness.
  • Damaged CHT sensor.
  • Improper harness connection.
  • Damaged PCM.
    • Symptoms
    – Engine Light ON (or Service Engine Soon Warning Light)
    P1290 Buick Description

    Indicates a CHT sensor circuit malfunction (shorted).

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