Circuit Description

Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Throttle Position (TP) sensor, and monitors the TP signal circuit for changes in throttle angle. TP sensor signal voltage should be about.5 volt at idle and 4.5 volts or greater at wide open throttle. DTC P0121 will set if TP sensor angle is greater than 7 percent at idle after attempting to auto-zero, or TP angle is greater than the following specified percentages at the given RPM for at least 6 seconds:

• 2 percent at 0 RPM
• 10 percent at 800 RPM
• 20 percent at 1600 RPM
• 25 percent at 2400 RPM
• 30 percent at 3200 RPM
• 35 percent at 4000-4800 RPM
• 40 percent at 5600 RPM
• 40 percent at 6400 RPM

For duplication of DTC, ensure:

• DTCs P0106, P0107, P0108, P0171, P0172, P0200, P0300, P0301, P0302, P0303, P0304, P0325, P0335, P0341, P0342, P0404, P0405, P0440, P0442, P0452, P0453, P0502, P0506, P0507, P0601, P0602 or P1441 are not set.
• Engine is running.
• ECT is greater than 68°F (20°C).
• TP stable at plus or minus 2 percent.
• MAP is less than 37 kPa.