The 2021 Lexus RX setting P0507 indicates the idle speed is consistently higher than the ECM's target. This luxury crossover uses electronic throttle control, and high idle typically points to air entering the intake outside normal throttle control.
Understanding P0507
P0507 sets when idle speed exceeds the target by a significant margin that the ECM can't correct by closing the throttle further. Additional air is entering the intake somewhere, whether through a leak or stuck component.
RX Engine Options
The 2021 RX offers 3.5-liter V6 (RX 350), 3.5-liter V6 hybrid (RX 450h), and turbocharged 2.0-liter (RX 300). Each has different potential leak points. The V6 engines are most common in North America.
Vacuum Leak Sources
Vacuum leaks allow unmetered air into the intake, raising idle speed. Common locations include intake manifold gaskets, PCV system hoses, brake booster line, and throttle body gasket. Cracked or deteriorated hoses are frequent culprits.
Throttle Body Issues
Carbon buildup can prevent the throttle plate from closing completely. Even a small gap allows excess air. Clean the throttle body and perform idle relearn using a compatible scanner.
Electronic Component Faults
A faulty throttle position sensor may report incorrect position. Sticky throttle plate linkage can hold the plate slightly open. The electronic throttle motor may not fully close on command.
Repair Costs
Vacuum hose replacement costs $50-200. Throttle body cleaning runs $150-300. Intake manifold gasket replacement ranges $400-800. Idle relearn procedure costs $50-150.