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P0120

Throttle/Pedal Position Sensor A Circuit Malfunction

Fault in the throttle position sensor (TPS) or pedal position sensor circuit.

SeverityCritical
CategoryEngine
Est. Repair Cost$100–$500
Code TypePowertrain
DIY RepairYes

⚡ Common Causes

  • ›Faulty throttle position sensor
  • ›Damaged throttle body
  • ›Wiring fault
  • ›Carbon buildup on throttle plate

⚠️ Symptoms

  • ›Rough idle
  • ›Poor acceleration
  • ›Hesitation or surging
  • ›Check engine light
  • ›Possible failsafe mode

✅ How to Fix — Step by Step

  • Step 1:Clean throttle body
  • Step 2:Check TPS wiring and connector
  • Step 3:Test TPS voltage sweep (0.5V–4.5V)
  • Step 4:Replace TPS or throttle body assembly

🔧 Diagnostic Tools Required

Using the correct diagnostic tools helps identify the root cause of P0120 before replacing parts unnecessarily. Always confirm the fault using live data and manufacturer-recommended diagnostic procedures.

💡 Pro Tip: Modern drive-by-wire systems use dual TPS sensors — both must read within spec of each other.

Repair Cost Estimate

Full Repair Estimate
$100–$500
DIY Possible?
YES
Severity
Critical

Frequently Asked Questions

What does OBD2 code P0120 mean?+
P0120 stands for Throttle/Pedal Position Sensor A Circuit Malfunction. Fault in the throttle position sensor (TPS) or pedal position sensor circuit.
What causes code P0120?+
Faulty throttle position sensor; Damaged throttle body; Wiring fault; Carbon buildup on throttle plate
How do I fix code P0120?+
Clean throttle body; Check TPS wiring and connector; Test TPS voltage sweep (0.5V–4.5V); Replace TPS or throttle body assembly
How much does it cost to fix P0120?+
Estimated repair cost for P0120 is $100–$500.
Is P0120 DIY-friendly?+
Yes — P0120 is generally DIY-friendly with basic tools.

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