All codes › P0121
P0121: Throttle/Pedal Position Sensor "A" Circuit Range/Performance
What it means
Throttle position sensor "A" reading doesn't match airflow or the second sensor; it's out of range.
Severity: High Surging or limp mode possible.
Common causes
- Worn TPS track (dead spot)
- Dirty throttle body
- Mismatch with sensor B
- Intake leak affecting comparison
Most common causes first. Exact causes vary by make, model and engine.
Can I fix it myself?
Sometimes DIY. Clean the throttle body; watch the TPS sweep on a scan tool for dead spots.
Repair cost
SEEDED ESTIMATE Roughly $190–$580
Most likely repair: throttle body (includes tps on most drive-by-wire cars). Diagnosis fees, taxes and other causes are not included.
| Line | Low | High | Basis |
|---|---|---|---|
| Throttle body (includes TPS on most drive-by-wire cars) | $140 | $344 | Typical listed retail range, source ($870–$1,222 performance units excluded) |
| Labor 0.5–1.5 hr | $50 | $240 | $100–$160/hr, shop survey |
⚠️ This is an editorial placeholder range for this type of repair. It is not based on real invoices or licensed pricing data yet. Real ranges will appear here once enough reader invoices for P0121 are verified.
Verified reader invoices for P0121: 0. Share your repair bill to help build real costs.
Tools that can read P0121
- ScanFixAI: Pro $29.99/mo or $249.99/yr
- OBDAI: Annual PRO bundle $299
- BlueDriver Pro Next-Gen: $119.95 list ($99.95 sale seen)
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