System: Powertrain (P-Code)
SAE Standard (Generic)
Family: Throttle Position Sensor Circuit
Code P0121: Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance
Diagnostic & Technical Explanation
Code P0121 (Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance) sets when the ECM detects an open, shorted, or out-of-range voltage, or an implausible rate of change, from a throttle body or accelerator pedal position sensor channel. Causes are a worn sensor track, a corroded connector, or chafed wiring between the sensor and the ECM.
First-listed procedure
Rank #1
Inspect and clean throttle/pedal position sensor connector
Easy DIY
This is the first procedure in the authored
consideration order, not a measured cause likelihood. Execute it only when its prerequisites
and diagnostic findings support it. Its cost and labor estimates (where known), the step-by-step procedure and the
remaining 2 procedure(s) are in the licensed dataset. Ordering context.
Full family: Throttle Position Sensor Circuit
What this page does not show
This page publishes the fault mechanism and the code index. The licensed dataset adds, for
every one of the 15,886 codes, the full authored repair set (56,729 procedures in total)
with the fields deliberately withheld here:
- Procedures 2..n after the first-listed procedure
- Aftermarket parts cost ranges in USD (
est_parts_cost_min/max_usd)
- Professional labor-hour estimates (
est_labor_hours)
- Step-by-step diagnostic and repair instructions
- Replacement-part mappings and catalog lookups
- 6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)