OBD-II Code · Sensors
P0221
Throttle Position Sensor "B" Range/Performance
Severity
medium
Worth booking. It costs fuel, emissions or comfort until it is fixed.
Can you drive it
Only if running normally
A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety.
Indicative cost (USD)
$100–$600
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
Secondary TP sensor signal does not track primary sensor.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
- Limp-home mode
- Stall on tip-in
Likely causes
- TPS driftMost common
- Throttle-body needs cleaning
- Wiring
Read the full diagnostic procedureP0221 means TPS sensor B is reporting a voltage that is in-range electrically but does not correlate with engine load, MAF airflow, or the TPS-A sign…
P0221 means TPS sensor B is reporting a voltage that is in-range electrically but does not correlate with engine load, MAF airflow, or the TPS-A signal — a rationality fault rather than an open/short.
The cheapest diagnostic is a slow-sweep test
with the engine off and ignition on, slowly open the throttle by hand (or by accelerator pedal on drive-by-wire) while watching both TPS-A and TPS-B on a graphing tool — any flat spot, glitch, or non-mirrored region in TPS-B's sweep is the defect. TPS-A should climb smoothly from ~0.5 V to ~4.5 V; TPS-B should descend (or ascend on some platforms) just as smoothly with no dropouts. Check the 5 V reference for sag under load and confirm sensor ground integrity (under 100 mV drop). Caveat: carbon buildup on the throttle plate can cause the plate to hang at a slightly different mechanical position than the PCM expects from learned closed-throttle, which trips P0221 without any actual sensor fault — always do an induction clean and throttle relearn before condemning the throttle body.
Vehicle-specific patterns2008-2013 GM 5.3L truck (LMG/LC9) with AFM — carbon coking around the throttle plate edge causes intermittent P0221; throttle-body service and idle/E…
- 2008-2013GM 5.3L truck (LMG/LC9) with AFM — carbon coking around the throttle plate edge causes intermittent P0221; throttle-body service and idle/ETC relearn via Tech 2 or equivalent resolves most cases.
- 2006-2011Toyota Tacoma 4.0L (1GR-FE) — the integrated TPS develops a dead spot around 15-20% opening; ETB replacement (22030-31010) is the documented fix.
- 2007-2012Nissan Altima 2.5L (QR25DE) — electronic throttle control actuator failure under TSB NTB10-082, ETB part 16119-JA00A.
- 2005-2010Ford Mustang 4.6L 3V — TPS-B nonlinearity from connector pin fretting; clean and apply dielectric grease before replacing the throttle body.
Estimated repair$90 to $550.
Look up another code
P0221 — frequently asked
What does a P0221 code mean?
Secondary TP sensor signal does not track primary sensor.
What causes a P0221 code?
Common causes: TPS drift; Throttle-body needs cleaning; Wiring.
What are the symptoms of a P0221 code?
Typical symptoms: Check engine light; Limp-home mode; Stall on tip-in.
Is it safe to drive with a P0221 code?
Only if running normally. A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety. Estimated repair: $100-$600.
How do I diagnose a P0221 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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