DTC P0123: Throttle Position (TP) Sensor Circuit High Input

Connect scan tool to Data Link Connector (DLC). Turn ignition on. Select TP sensor parameter on scan tool. Observe scan tool display while depressing accelerator pedal to full throttle position. If scan tool display remains at 100 percent, go to next step. If scan tool display changes from zero to 100 percent, check for an intermittent problem. See TESTS W/O CODES article.
Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on. Using DVOM, measure voltage between ground and Gray/Red wire at TP sensor harness connector. If voltage is 4.75-5.25 volts, test TP sensor. See DTC P0121 : THROTTLE POSITION (TP) SENSOR SYSTEM PERFORMANCE. If TP sensor is okay, go to step 4). If voltage is not as specified, go to next step.
Check Gray/Red wire for a short to power. Repair as necessary. If wire is okay, replace PCM and retest system.
Check Gray wire for a short to Gray/Red wire. Check for an open in Gray/Yellow wire (Brown wire on some models), or poor TP sensor harness connection. Repair as necessary. If wires and connections are okay, replace PCM and retest system.