Circuit Description

Throttle Position (TP) sensor is a variable resistor which monitors throttle opening. ECM determines vehicle driving condition and adjusts air/fuel mixture accordingly. DTC is set when ECM consistently detects less than .1 volt or more than 4.9 volts on VTA circuit. If DTC P0120 exists, ECM will operate in fail-safe mode. Possible causes are:

• TP sensor circuit is open or shorted.
• Defective TP sensor.
• Defective ECM.