P0570

P0570 is set when the cruise control system reads an implausible state on the brake-switch input — typically the stop-lamp / brake-light switch that doubles as the cruise-disengage signal. Normal brake switch behavior: pedal up (not pressed) reads 0V on the cruise input (open circuit) and 12-14V on the stop-lamp input (or the inverse on dual-channel switches, where one pole opens as the other closes); pedal down (pressed) reads battery voltage on the cruise input (closed circuit) and 0V on the stop-lamp input. Cheapest-first ladder: scan-tool live data for brake-switch state and compare against actual pedal position — at rest the switch should read "not applied"; lightly touch the pedal and watch for a clean transition to "applied" within a few mm of travel. If the state flickers, chatters, or reports both "applied" and "not applied" simultaneously (common on dual-channel switches where one pole fails), the switch is worn. Backprobe both poles of the switch with a DMM, work the pedal slowly, and watch for clean make/break transitions — anything below 11V on the supply side or above 0.5V on the open side is a failing switch. Inspect the switch's bumper/plunger on the pedal bracket; the plastic plunger commonly cracks or wears short and the switch reads "applied" at rest. Expensive-misdiagnosis caveat: a flickering brake switch will not only kill cruise control but will trigger torque-management and transmission shifts, ABS event flags, and on some platforms (Toyota in particular) an unintended-acceleration concern in the freeze frame — verifying the switch is healthy before chasing transmission or throttle codes saves hours.

Vehicle-specific patterns: 2005-2010 Toyota and Lexus across multiple platforms (Camry, Avalon, RAV4, ES350, IS250) are the textbook P0570 / brake-switch case — the OEM brake switch plunger wears short, the switch reads "applied" at rest, cruise won't engage, and the ECM logs the code; Toyota issued multiple TSBs and offered an extended warranty / recall on affected VINs after the 2009-2011 unintended-acceleration investigations. 2009-2014 Ford F-150 (and similar-era Edge, Explorer, Expedition) commonly throws P0570 from stop-lamp switch wear at the pedal bracket — the cheap fix is a $25 switch from any parts store, but the part has to seat perfectly against the pedal arm or the code returns. 2007-2013 Chevy/GMC trucks (Silverado, Sierra, Tahoe, Suburban) throw P0570 from the same generic stop-lamp switch wear plus occasional brake-pedal-position sensor failures on platforms equipped with electronic throttle. 2010-2017 RAM 1500/2500 also commonly throws P0570 from the TIPM-routed brake switch circuit when the under-hood module corrodes the relay contacts. Estimated repair: $30 (DIY brake switch replacement) to $400 (TIPM repair or pedal-bracket replacement on a RAM).