The Throttle Position (TP) sensor provides a voltage signal which changes relative to the throttle blade angle. The signal voltage varies from about 0.5 volt at idle to about 4.0 volts at Wide Open Throttle (WOT).

The TP signal is one of the most important inputs used by the VCM for fuel control and for most of the VCM control outputs. This DTC is a type D DTC

The DTC sets when the TP sensor signal voltage is greater than about 4.8 volts and the MAP is less than 51 kPa for a period greater than 4 seconds with engine running.

The VCM stores the DTC in History if the VCM detects an intermittent problem.

The VCM turns OFF the MIL after 3 consecutive driving trips without a fault condition present. A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (the coolant temperature has risen 22°C (40°F) from the start-up coolant temperature and the engine coolant temperature exceeds 71°C (160°F) during that same ignition cycle) or the scan tool clearing feature has been used.

The VCM pins GRY 12 and GRY 27 are spliced together inside of the VCM. When checking one of these circuits for a problem, also check the other circuit and the components on the circuit.

The scan tool reads the throttle position in volts. The scan tool should read about 0.45 to 0.85 volt with the throttle closed and the ignition switch turned ON or at idle. The voltage should increase at a steady rate as the throttle is moved toward the Wide Open Throttle (WOT).

Also, some scan tools will read the throttle angle. 0% = closed throttle. 100% = WOT.

Scan the TP sensor while depressing the accelerator pedal with the engine turned OFF and the ignition turned ON. The display should vary from below the 1.25 volts (1250 mV) when the throttle is closed to over 4.5 volts (4500 mV) when the throttle is held at WOT position.

A DTC P0123 will result if the TP ground circuit is open or the TP signal circuit is shorted to the voltage.

A DTC P0122 will result if there is an open or a short to ground in the 5 volt reference circuit or the TP sensor signal circuit.

Refer to Intermittent Conditions .

The numbers below refer to the step numbers in the diagnostic table.

2. If the TP signal is greater than 4.8 volts, then the fault is present.

3. With the TP sensor disconnected, the TP signal voltage should go low if the VCM and wiring is OK.

4. Probing the TP sensor ground circuit with a test lamp checks the 5 volt return circuit. This step isolates a faulty sensor, VCM or an open TP sensor ground circuit.