P1564

P1564 on a Lexus/Toyota means the Acceleration Sensor — specifically the steering-wheel-mounted cruise-control acceleration tilt sensor that lets the driver tap the cruise stalk to bump the set speed up or down — has reported a signal out of valid range, and the cruise control system disables itself as a safety response. The sensor is a small Hall-effect or potentiometric tilt sensor inside the cruise stalk assembly, and on the platforms that use it (mostly 1990s and early-2000s Lexus LS/GS/IS), it feeds a 0-5V analog signal to the cruise ECU; valid range is typically 0.5V to 4.5V with center at 2.5V, and signals outside 0.2-4.8V for more than 1 second throw the code and kill cruise. Cheapest-first ladder: (1) check the cruise main switch with cruise OFF — main switch open reads 0V at the cruise ECU input, switched ON reads 5V. If the main switch reads anything between, the stalk contacts are dirty (cheap clean with contact cleaner) or the stalk module is failing. (2) Operate the cruise stalk through its full range with a scan tool reading the accel-sensor PID — a healthy sensor sweeps smoothly from ~0.5V to ~4.5V; dropouts to 0V or jumps to 5V indicate a worn pot or bad solder joint inside the stalk. (3) Inspect the spiral cable (clockspring) behind the steering wheel for chafe — a partial short in the cruise wires running through the clockspring is a common root cause and mimics a bad sensor perfectly. Expensive-misdiagnosis caveat: don't replace the cruise ECU for P1564 — the cruise ECU virtually never fails internally; the fault is in the stalk, the clockspring, or the harness from the column to the ECU about 98% of the time, and a $300-$600 cruise ECU swap is the wrong call.

Vehicle-specific patterns: 1995-2000 Lexus LS400 and 2001-2006 LS430 are the most common P1564 platforms — the cruise stalk module's tilt sensor wears around 150K mi and the symptoms start as intermittent cruise dropout before the code finally latches. 1993-2005 Lexus GS300/GS400/GS430 share the same stalk family and the same wear pattern. 1999-2005 Lexus IS300 (2JZ-GE) throws P1564 less often but with the same root cause when it does. 2000-2007 Toyota Avalon and 2002-2009 Camry XLE with adaptive cruise variants share fragments of the same architecture and can throw P1564 from clockspring chafe. Estimated repair: $80 to $400.