DTC P0123: Throttle Position (TP) Circuit High Input

NOTE: On Esteem 1.6L and Swift, if DTC P0108, P0113, P0118, P0123 and/or P0450 are set together, Check PCM harness connector C22 terminal No. 9 (Green/Red wire on Esteem, or Light Green/Black wire on Swift) for an open circuit.

Connect scan tool to Data Link Connector (DLC). Turn ignition on. Observe throttle valve opening percentage on scan tool while slowly opening throttle valve to fully open position. If display increases to 100 percent (Esteem 1.8L), or 96 percent or greater (Esteem 1.6L and Swift), go to next step. If display reading is less than 100 percent (Esteem 1.8L), or 96 percent (Esteem 1.6L and Swift), check for an intermittent problem. Go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on. Measure voltage between Gray and Pink/Green wires (Esteem 1.8L), ground and Pink/Green wire (Esteem 1.6L) or ground and Light Green wire (Swift) at TP sensor harness connector. Reading should be 4-6 volts. If reading is as specified, go to next step. If reading is not as specified, check wire for short to voltage and retest system. If wire is okay, go to next step.
On Esteem 1.8L, go to next step. On Esteem 1.6L and Swift, measure voltage between ground and Gray (Esteem) or Light Green/White (Swift) wire at TP sensor harness connector. Reading should be 4-6 volts. If reading is as specified, go to next step. If reading is not as specified, check wire for an open. If wire is okay, replace PCM and retest system.
Measure resistance between specified TP sensor terminals. See Figure . See TP SENSOR RESISTANCE table. If resistance is not as specified, replace TP sensor. If resistance is as specified, check Orange wire (Esteem 1.8L), Green/Red wire (Esteem 1.6L) or Light Green/Black wire (Swift) for an open. If wire is okay, replace PCM. Retest system.