Diagnostic Aids

Codes 21 and 23 stored at the same time could be the result of an open in Gray/Yellow wire.

When replacing IAT sensor, check TEMPERATURE TO RESISTANCE VALUES table. A "shifted" sensor could result in poor driveability complaints.

Fig 1: Code 23 - Schematic Intake Air temperature Sensor Circuit, Low Temp. Indicated

Fig 2: Code 23 - Flow Chart Intake Air temperature Sensor Circuit, Low Temp. Indicated