P0121 — OBD-II trouble code

A generic powertrain OBD-II trouble code. Below are the vehicles and failure patterns where owners report it, drawn from NHTSA complaints.

In ProblemsByVin's analysis of the NHTSA owner-complaint record, owners cite P0121 across 18 vehicle failure patterns. Diagnostic codes in complaints are reported by owners and are unverified — they point to where this code shows up, not a confirmed diagnosis. Open a page below for the full pattern (symptoms, mileage, repair costs owners cite).

Vehicles where owners report P0121 18 patterns

2015 Jeep Patriot

electrical — Electronic Throttle Control (ETC) light / loss of acceleration / limp mode

2015 Jeep Compass

electrical — Throttle control failure with stalling

2011 Chevrolet Traverse

electrical — Ignition coil failure causing engine power reduction and limp mode

2010 Chevrolet Traverse

electrical — Engine stalls or shuts down while driving

2010 Toyota Camry

fuel system — Sudden deceleration

2009 Chevrolet Impala

cruise control — Accelerator Pedal Position Sensor / Throttle Body Failure

2009 Toyota Corolla

cruise control — Sudden unintended acceleration / stuck accelerator pedal

2008 Toyota Yaris

electrical — Engine stalling and no-accelerate conditions

2007 Chevrolet Silverado

powertrain — Electrical loss of power and instrument cluster failures

2007 GMC Yukon

powertrain — Throttle body / pedal sensor failure causing limp mode

2006 Chevrolet Impala

electrical — Reduced Engine Power / Throttle Actuator Control Module (TACM) Failure

2006 Chevrolet Malibu

engine — Random stalling / loss of power with limp-mode messages

2006 GMC Envoy

powertrain — Reduced Engine Power mode / throttle body / sensor faults

2006 Toyota Corolla

fuel system — Throttle body / throttle position sensor failure

2005 Ford Expedition

electrical — Electronic Throttle Control (ETC) System Failures – Loss of Power/Acceleration

2005 Ford F-150

electrical — Engine Failsafe Mode / Stalling and Loss of Power

2005 Ford F-150

cruise control — Unintended sudden acceleration when braking

2005 Toyota Sienna

electrical — Electronic throttle control system malfunction (P0121 code)

Codes are pulled from what owners wrote in their NHTSA filings — they're allegations, not a shop diagnosis. Always confirm with a live scan. Browse all diagnostic codes →