DTC 23

Circuit Description:
The Throttle Position Sensor (TPS) is a variable resistor that signals the ECM the degree of throttle opening. The sensor is connected to a 5 volt reference and has the highest resistance at closed throttle. At wide open throttle, the resistance is lowest and output to the ECM will be near 5 volts.
Code 23 means that the ECM has seen the following:
^ Voltage not between 0.25 and 1.35 volts at ECM terminal "A2."
^ For a time in excess of 30 seconds.
^ Engine speed between 550 and 650 rpm.

Test Description:
Numbers below refer to the circled numbers on the diagnostic chart.
1. Confirms Code 23 and that fault is present.
2. Will determine if sensor signal line is shorted to ground.
3. Refer to the procedure for adjusting the throttle position sensor.

Diagnostic Aids:
^ Disregard a Code 23, if "Service Engine Soon" light goes out as soon as the throttle is returned to idle.