Circuit Description

Throttle Position (TP) sensor is a potentiometer whose resistance changes along with throttle valve position. PCM provides a 5-volt reference voltage to TP sensor. PCM reads voltage across sensor and converts it into a reference for throttle position. When TP sensor resistance decreases, throttle valve opening is increasing to Wide Open Throttle (WOT) and voltage being monitored at PCM increases. When TP sensor resistance increases, throttle valve opening is decreasing to idle and voltage being monitored at PCM decreases.

DTC will set when:

• Engine speed is 1600-3000 RPM.
• ECT is greater than 158°F (70°C).
• IAT is 14-158°F (-10 to 70°C).
• Fuel level is greater than 25 percent.
• Barometric pressure is greater than 11 psi (75 kPa).
• MAP change is less than 1.9 psi (13 kPa) per 16 firing events.
• Difference between expected TP sensor and actual input is greater than 20 degrees.
• Conditions are present for at least 3 seconds.

When DTC sets, MIL will illuminate after 2 consecutive ignition cycles in which diagnostic runs with active fault. PCM will record operating conditions at time of diagnostic failure and store information in freeze frame buffer.