P1125

P1125 on a Toyota means the Throttle Control Motor Circuit (ETCS-i electronic throttle control system, intelligent) has detected an open or short in the throttle motor drive circuit — the H-bridge driver inside the ECM can't get the commanded current through the motor windings. ETCS-i uses a brushed DC motor inside the throttle body that runs typically 0.5-3A through an H-bridge driver, with the ECM monitoring motor current as a closed-loop signal; when commanded current and measured current diverge by more than the FSM threshold (usually >0.3A for >100ms) P1125 sets and the system falls back to limp-home idle of around 1,000-1,200 RPM with no pedal response above ~30% throttle. Cheapest-first ladder: (1) scan live data for commanded throttle blade angle versus actual throttle position sensor (TPS) reading — a healthy ETCS-i tracks within <5 degrees deviation across the full 0-90 degree blade sweep; if commanded reads 45 degrees and actual reads 8 degrees while motor current is pinned at 3A, the motor is binding or the blade is carbon-stuck. (2) Pull the throttle body, inspect the bore and back side of the blade for carbon buildup — Toyota ETCS-i throttle bodies foul with carbon at 80K-120K mi and the blade physically can't open against the deposits, which the ECM reads as a motor-circuit fault. (3) Ohm the motor windings at the connector (should read ~1-5 ohms cold per FSM); open circuit means the motor is dead, very low resistance means a shorted winding. Expensive-misdiagnosis caveat: do the throttle body re-learn AFTER cleaning the bore — Toyota ETCS-i throttle bodies foul with carbon at 80K-120K mi; cleaning + relearn restores adaptation without replacing the $400 throttle body, but skipping the relearn after a clean leaves the ECM with stale adaptation values and the code can come right back.

Vehicle-specific patterns: 2002-2009 Toyota Camry/Solara with the 2AZ-FE 2.4L is the most common P1125 ticket — the throttle bore cokes up at the PCV inlet side and the blade hangs. 2004-2010 Highlander with the 2GR-FE 3.5L V6 and Sienna 3.3/3.5L throw P1125 with similar carbon-fouling timing (~100K mi) and respond to a clean + relearn 80% of the time. 2006-2012 RAV4 with the 2AR-FE 2.5L throws P1125 with a slightly different pattern — the failure tends to be the motor itself (brushes worn) rather than the bore, so cleaning helps less and a throttle body replacement is more often the durable fix. 2001-2006 Lexus IS/GS with the 2JZ-GE and 3GR-FE family throw P1125 from connector corrosion at the throttle body more than from carbon. Estimated repair: $80 to $550.