P0120 - Throttle/Pedal Position Sensor/Switch A Circuit Malfunction

Problem detected in TPS/APP circuit A.

Treat the code as the starting point: compare symptoms, likely causes, and repair paths before pricing parts or moving into an estimate.

Code Overview

Problem detected in TPS/APP circuit A.

Common Causes

• TPS/APP sensor failed
• Wiring/connectors issue
• Throttle body contamination (some systems)

Diagnostic Steps

1. Check TPS/APP readings sweep smoothly
2. Inspect harness near throttle body
3. Check for 5V reference/ground
4. Perform throttle relearn if applicable

Likely Repairs & Cost Guides

Use symptoms, scan data, and quick checks to confirm the likely repair path before pricing parts. The estimator helps compare repair paths before replacing anything unnecessarily.

Related OBD Codes

Browse nearby code-family pages when the same fault pattern overlaps across systems, such as misfire, lean fuel trim, EVAP sealing, cooling, or charging faults.

Next Steps

Move from code lookup to diagnosis, then estimate the likely repair only after symptoms, causes, and checks point to the same path.