P1121

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

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.

CONDITIONS FOR SETTING THE DTC

^ Engine running.

^ TP voltage is greater than 4.9 V

ACTION TAKEN WHEN THE DTC SETS

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

CONDITIONS FOR CLEARING THE MIL/DTC

^ A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during the same ignition cycle.

^ Use the scan tool Clear Information function.

^ Disconnect the VCM battery feed for 30 seconds.

DIAGNOSTIC AIDS

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 was closed to over 4.5 volts (4500 mV) when the throttle is held at WOT position.

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

Refer to the Symptoms. Testing and Inspection

TEST DESCRIPTION

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.