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DTC/P0122

P0122: Throttle/Pedal Position Sensor/Switch A Circuit Low Input

Quick Answer
Moderata GravitàNon sicuro da guidareImpianto elettrico

P0122 means the ECU is seeing an abnormally low voltage on throttle position sensor circuit A, typically under 0.2V when it expects 0.5V to 4.5V. Most cars drop into limp mode with capped throttle.

Scansiona la tua auto in circa 60 secondi: scopri se P0122 è davvero presente, quanto è urgente e quanto dovrebbe costare la riparazione.

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Cosa significa P0122?

P0122 means the ECU is seeing an abnormally low voltage on throttle position sensor circuit A, typically under 0.2V when it expects 0.5V to 4.5V. Most cars drop into limp mode with capped throttle.

P0122 è un codice diagnostico di guasto relativo a impianto elettrico, classificato con gravità moderate. Quando la centralina (ECU) del tuo veicolo rileva questa condizione, memorizza P0122 e accende la spia motore.

Quali sono i sintomi di P0122?

Se il tuo veicolo ha attivato P0122, potresti notare uno o più di questi sintomi:

  • Check Engine Light on, often paired with a throttle or EPC warning
  • Reduced engine power / limp mode with throttle capped around 25 to 40%
  • Rough or hunting idle between 500 and 1500 rpm
  • No response or long delay when pressing the accelerator
  • Stalling at idle or when coming to a stop
  • Slight decrease in fuel economy from open-loop fueling
  • Transmission holding gears longer or shifting harshly because it has no load signal

Cosa causa P0122?

Ecco le cause più comuni di P0122:

altaFaulty throttle position sensor or worn contacts inside the throttle body
altaCorroded, loose, or backed-out connector at the throttle body
mediaBroken or chafed signal wire between TPS and ECU
mediaOpen or shorted 5V reference wire from the ECU
bassaBad ground on the TPS circuit
bassaFailed ECU (rare, diagnose last)

È sicuro guidare con P0122?

No, risolvi subito il problema. The ECU usually forces the car into limp mode with reduced power and a locked idle. You can limp home, but hard acceleration and highway merging become risky.

Come si diagnostica P0122?

Segui questi passaggi per individuare la causa principale di P0122:

  1. Read all stored codes and note companion codes such as P0113, P0222, or P2135
  2. Watch live data for TPS1 voltage with key on, engine off. Below 0.2V confirms the low input
  3. Wiggle the throttle body connector and harness while watching live data to catch intermittent faults
  4. Backprobe the TPS signal, 5V reference, and ground pins with a multimeter. Reference should read 4.9 to 5.1V
  5. If reference and ground are good but signal stays near 0V, replace the TPS or throttle body
  6. If the 5V reference is missing, check the wiring back to the ECU for a short to ground
  7. After repair, clear codes and run the throttle body relearn per the manufacturer procedure
  8. Road test and confirm TPS voltage sweeps smoothly from ~0.5V at closed throttle to ~4.5V at WOT

Quanto costa riparare P0122?

I costi di riparazione di P0122 variano a seconda della causa principale e del tuo veicolo. Ecco le stime tipiche:

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Clean and reseat throttle body connector €0–€10 €0–€40 €0–€50 Facile
Replace standalone throttle position sensor €30–€120 €40–€90 €70–€210 Facile
Replace electronic throttle body assembly €180–€550 €80–€180 €260–€730 Moderata
Repair damaged wiring or connector pins €10–€40 €60–€180 €70–€220 Moderata
ECU diagnosis and replacement (worst case) €400–€1200 €100–€250 €500–€1450 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

P0122 su veicoli specifici

P0122 si comporta in modo diverso a seconda del tuo veicolo. Seleziona la tua auto qui sotto per cause specifiche del modello, problemi noti e stime dei costi adeguate:

Volkswagen

P0122 su Volkswagen Golf

2005-2015 (Mk5/Mk6, 1.4 TSI CAVA/CAXA and 2.0 TDI CBEA/CJAA)

The EPC light comes on with P0122 on these Golfs. On 1.4 TSI engines the throttle body actuator motor brushes wear out around 120,000 to 180,000 km. VW part 03C 133 062 is the common replacement.

Cosa causa P0122 su una Volkswagen Golf?

Volkswagen GolfWorn throttle actuator motor brushes on 1.4 TSI (CAVA/CAXA)
Volkswagen GolfCorrosion inside the throttle body connector after wet-weather driving

Costo di riparazione di P0122 per Volkswagen Golf

Costi stimati per i proprietari di Volkswagen Golfadeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Volkswagen

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Clean and reseat throttle body connector €0–€12 €0–€48 €0–€60 Facile
Replace standalone throttle position sensor €36–€144 €48–€108 €84–€252 Facile
Replace electronic throttle body assembly €216–€660 €96–€216 €312–€876 Moderata
Repair damaged wiring or connector pins €12–€48 €72–€216 €84–€264 Moderata
ECU diagnosis and replacement (worst case) €480–€1440 €120–€300 €600–€1740 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Ford

P0122 su Ford F-150

2004-2010 (5.4L 3V Triton and 4.6L)

Ford issued TSB 08-7-6 covering electronic throttle body concerns on these trucks, with a revised throttle body part number 9L3Z-9E926-A. The APP (accelerator pedal position) sensor is also a known failure point.

Cosa causa P0122 su una Ford F-150?

Ford F-150Failed accelerator pedal position sensor rather than the TPS itself
Ford F-150Chafed harness where it passes near the intake manifold

Costo di riparazione di P0122 per Ford F-150

Costi stimati per i proprietari di Ford F-150adeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici Ford

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Clean and reseat throttle body connector €0–€11 €0–€44 €0–€55 Facile
Replace standalone throttle position sensor €33–€132 €44–€99 €77–€231 Facile
Replace electronic throttle body assembly €198–€605 €88–€198 €286–€803 Moderata
Repair damaged wiring or connector pins €11–€44 €66–€198 €77–€242 Moderata
ECU diagnosis and replacement (worst case) €440–€1320 €110–€275 €550–€1595 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Toyota

P0122 su Toyota Camry

2007-2017 (2.5L 2AR-FE and 3.5L 2GR-FE)

The TPS is integrated into the throttle body (Toyota part 22030-0H030 range) and not sold separately. Toyota's service procedure requires an idle air volume learn after replacement or battery disconnect.

Cosa causa P0122 su una Toyota Camry?

Toyota CamryIntegrated TPS failure inside the electronic throttle body
Toyota CamryWater intrusion through a leaking cowl seal reaching the engine harness
BMW

P0122 su BMW 3-Series

2006-2013 (N52, N54, N55)

BMW uses dual redundant TPS in both the pedal and throttle actuator. P0122 usually pairs with P2135 and drops the car into a restrictive failsafe. Water leaks into the E-box under the cowl are a well-documented cause on E90s.

Cosa causa P0122 su una BMW 3-Series?

BMW 3-SeriesFailed throttle actuator (DME-controlled) on N54/N55
BMW 3-SeriesWater in the E-box corroding DME connector pins

Costo di riparazione di P0122 per BMW 3-Series

Costi stimati per i proprietari di BMW 3-Seriesadeguato al rialzo rispetto alla media a causa dei prezzi dei ricambi specifici BMW

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Clean and reseat throttle body connector €0–€14 €0–€56 €0–€70 Facile
Replace standalone throttle position sensor €42–€168 €56–€126 €98–€294 Facile
Replace electronic throttle body assembly €252–€770 €112–€252 €364–€1022 Moderata
Repair damaged wiring or connector pins €14–€56 €84–€252 €98–€308 Moderata
ECU diagnosis and replacement (worst case) €560–€1680 €140–€350 €700–€2030 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Honda

P0122 su Honda Civic

2006-2015 (R18A 1.8L, 8th and 9th gen)

Uncommon on the Civic, but when it appears the throttle body assembly (Honda part 16400-RNA-A01) is the usual culprit. Honda requires the idle learn procedure (ignition on 2 minutes, then 5 minutes at operating temp) after any throttle work.

Cosa causa P0122 su una Honda Civic?

Honda CivicCarbon buildup preventing the throttle plate from returning to true closed position
Honda CivicCracked solder joint on the TPS board inside the throttle body

Costo di riparazione di P0122 per Honda Civic

Costi stimati per i proprietari di Honda Civicadeguato al ribasso rispetto alla media a causa dei prezzi dei ricambi specifici Honda

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Clean and reseat throttle body connector €0–€9 €0–€36 €0–€45 Facile
Replace standalone throttle position sensor €27–€108 €36–€81 €63–€189 Facile
Replace electronic throttle body assembly €162–€495 €72–€162 €234–€657 Moderata
Repair damaged wiring or connector pins €9–€36 €54–€162 €63–€198 Moderata
ECU diagnosis and replacement (worst case) €360–€1080 €90–€225 €450–€1305 Professionale

Prezzi stimati al March 2026. I costi variano in base alla regione, al veicolo e all'officina.

Questi codici compaiono spesso insieme a P0122 o indicano problemi correlati:

P0121P0123P0124P2135P0222

Domande frequenti su P0122

Can I just drive with P0122 until the weekend?

You can move the car short distances, but limp mode caps power and makes merging or overtaking dangerous. Fix it before any highway driving.

Will disconnecting the battery clear P0122 for good?

It'll clear the light, but if the sensor or wiring is faulty the code returns within minutes of driving. You're masking the problem, not fixing it.

Do I need a throttle relearn after replacing the throttle body?

Yes, on almost every drive-by-wire vehicle. Without the relearn the idle will hunt or stall. Most OBD2 apps with bidirectional control can run it in under a minute.

Why did P0122 appear right after I cleaned my throttle body?

The connector probably wasn't fully seated, or carb cleaner seeped into the TPS. Reseat the plug and let it dry overnight before condemning parts.

Can a weak battery or bad alternator trigger P0122?

Yes. If system voltage drops below about 10V during cranking or under load, the 5V reference can sag and log a low-input code. Load-test the battery before chasing sensors.

Leggi le nostre guide dettagliate

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