P2101: How to Diagnose & Fix — Throttle Actuator "A" Control Motor Circuit Range/Performance

This page previously presented one 2004-2009 electronic-throttle-body failure pattern as established fact. The audited official material does not verify that broad cause or model-year scope. It does show a direct safety conflict: NHTSA manufacturer-communication record 10017595 identifies Jaguar bulletin XJ303-10 for the 2004 XJ as “Electronic Throttle Body - Cleaning Prohibited.” Treat throttle symptoms as a reason for model-year-specific diagnosis, not proof that the throttle body needs cleaning or replacement.

The S65 engine's throttle body actuators have a design flaw in the internal gears that causes premature wear and electronic overload. The S65 uses individual throttle bodies for each cylinder bank, and actuator failure is extremely common. When failure occurs, the engine goes into limp mode with reduced power output.

The electronic throttle body on the XK develops position sensor failures causing erratic throttle response, limp mode, and check engine lights. The dual-track position sensor wears internally, sending conflicting signals to the engine management system.

Owners report sudden reduced power, poor throttle response, and limp-home behavior due to electronic throttle body contamination/wear or throttle actuator control faults. The issue can be intermittent and may clear after a key cycle, then recur, which is a common pattern in NHTSA complaints and owner reports. It often sets throttle/ETC-related DTCs and can be triggered by carbon buildup or failing throttle position sensing.

Owners report sudden loss of power with a wrench light and reduced throttle response, often while cruising or accelerating. NHTSA complaints and Ford service information describe electronic throttle body internal faults (TPS/actuator) that can trigger ETC failsafe and limp mode on 3.7L Ti-VCT Transits. The condition may be intermittent at first and then become frequent, especially with heat/soak and higher mileage.