P0124

P0124 is the intermittent TPS code, set when the ECM saw an out-of-range TPS signal that came back within range before it could latch a hard P0122 or P0123, and the fault has occurred often enough to trip the diagnostic monitor. These are diagnosis-heavy because the fault is rarely present on the lift. Cheapest-first ladder: wiggle-test the TPS connector and the 12 inches of harness behind it with engine running and a scan tool recording TPS voltage; any momentary spike to 4.9V or dropout to 0V confirms the fault zone. Inspect the connector for pushed-back terminals (a pin that looks seated but has retracted 1-2mm into the plastic shell is the classic intermittent failure mode), and check for green corrosion in the contacts. On cable-actuated TPS, slowly sweep the pedal while watching live voltage; any flat spot, jump, or dropout in the 0.5V-4.5V sweep is a worn potentiometer. On ETC, the ECM compares TPS1 to TPS2 across the full pedal sweep, so a glitch on either channel will set P0124 even if the other channel reads cleanly. Leave a scan tool recording freeze-frames during the customer's normal drive cycle for 1-3 days if bay testing is clean. Don't replace the throttle body for P0124 without a wiggle test first, because the sensor is usually fine and the connector or harness is the actual fault.

Vehicle-specific patterns: 2002-2008 Jeep Grand Cherokee 4.7L sees P0124 from pushed-back terminals in the TPS connector that lose contact under engine vibration. 2004-2010 Ford F-150 5.4L 3V sees P0124 from harness chafe at the ETC connector where the wiring crosses an intake manifold rib, the signal intermittently grounds against the rib. 2007-2013 GM Silverado 5.3L sees P0124 from a cracked solder joint inside the ETC throttle body that opens and closes with thermal cycling, and from connector seal failure admitting moisture into the contacts. 2008-2014 Toyota Tundra 5.7L 3UR-FE sees P0124 from the integrated TPS element aging past 120k miles with intermittent wiper dropout at part throttle. Estimated repair: $50 to $500.