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DTC/P0123

P0123: Throttle/Pedal Position Sensor/Switch A Circuit High Input

Quick Answer
Moderata GravitàNon sicuro da guidareImpianto elettrico

P0123 means the ECU sees TPS 'A' signal voltage above the upper threshold (typically 4.8V of the 5V reference). The computer ignores the throttle input and falls back to limp mode.

Scansiona la tua auto in circa 60 secondi: scopri se P0123 è davvero presente, quanto è urgente e quanto dovrebbe costare la riparazione.

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Cosa significa P0123?

P0123 means the ECU sees TPS 'A' signal voltage above the upper threshold (typically 4.8V of the 5V reference). The computer ignores the throttle input and falls back to limp mode.

P0123 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 P0123 e accende la spia motore.

Quali sono i sintomi di P0123?

Se il tuo veicolo ha attivato P0123, potresti notare uno o più di questi sintomi:

  • Check Engine Light on, often with a throttle or wrench warning
  • Reduced engine power / limp mode with RPM capped around 1200-1500
  • Erratic or hesitant acceleration
  • Engine surges or hunts at idle
  • Pedal feels dead - no response above light throttle
  • Hard starting or immediate stall after start
  • Cruise control disabled

Cosa causa P0123?

Ecco le cause più comuni di P0123:

altaFaulty throttle position sensor (worn resistive track or internal short to the 5V reference)
altaCorroded or spread pins in the TPS/throttle body connector
mediaTPS signal wire shorted to the 5V reference or to battery voltage
mediaOpen or high-resistance sensor ground circuit
bassaFailed drive-by-wire throttle body actuator assembly
bassaPCM 5V reference or internal A/D fault

È sicuro guidare con P0123?

No, risolvi subito il problema. You can drive short distances, but most vehicles trigger limp mode with reduced throttle response. Sudden power loss is possible, so get it diagnosed before longer trips.

Come si diagnostica P0123?

Segui questi passaggi per individuare la causa principale di P0123:

  1. Scan for all stored codes and freeze frame. Note if P0122, P0222 or P2135 are set alongside - that changes the diagnostic path
  2. Key on, engine off: watch TPS1 voltage on the scan tool. Above ~4.8V at closed throttle confirms the fault
  3. Inspect the TPS connector for bent pins, green corrosion, or water intrusion
  4. Backprobe the 5V reference at the TPS - should read 4.9-5.1V. If it reads battery voltage, the reference is shorted
  5. Check sensor ground continuity to battery negative (should be under 0.1Ω, voltage drop under 50mV with key on)
  6. Unplug the TPS. Signal voltage at the ECU pin should drop to near 0V. If it stays high, the signal wire is shorted to voltage between sensor and PCM
  7. If wiring checks out, substitute a known-good TPS or throttle body and recheck
  8. Only after all above, suspect PCM 5V reference or A/D converter failure

Quanto costa riparare P0123?

I costi di riparazione di P0123 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 TPS connector, apply dielectric grease €0–€15 €0–€60 €0–€75 Facile
Replace standalone throttle position sensor (cable throttle) €40–€180 €40–€120 €80–€300 Facile
Replace complete electronic throttle body (drive-by-wire) €180–€650 €80–€220 €260–€870 Moderata
Repair TPS wiring harness (short or open circuit) €20–€90 €90–€260 €110–€350 Moderata
PCM replacement and reprogram €500–€1400 €150–€350 €650–€1750 Professionale

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

P0123 su veicoli specifici

P0123 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

P0123 su VW Golf

2004-2015 (Mk5/Mk6)

1.4 TSI (CAXA/CAVD) and 2.0 TDI (CBEA/CJAA) throttle body connectors corrode where the harness routes near the coolant flange. VCDS measuring block 060 typically shows implausible angle-sensor 2 voltage.

Cosa causa P0123 su una VW Golf?

VW GolfCorroded 6-pin throttle body connector
VW GolfFailed throttle body (03C133062-family) requiring basic setting via VCDS after replacement

Costo di riparazione di P0123 per VW Golf

Costi stimati per i proprietari di VW 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 TPS connector, apply dielectric grease €0–€18 €0–€72 €0–€90 Facile
Replace standalone throttle position sensor (cable throttle) €48–€216 €48–€144 €96–€360 Facile
Replace complete electronic throttle body (drive-by-wire) €216–€780 €96–€264 €312–€1044 Moderata
Repair TPS wiring harness (short or open circuit) €24–€108 €108–€312 €132–€420 Moderata
PCM replacement and reprogram €600–€1680 €180–€420 €780–€2100 Professionale

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

Ford

P0123 su Ford F-150

2004-2010

5.4L 3V Triton trucks show P0123 with wiper-track wear inside the electronic throttle body. Ford TSB 08-7-6 addresses throttle body replacement for related surging/limp mode complaints.

Cosa causa P0123 su una Ford F-150?

Ford F-150Worn TPS internal resistive track inside the ETB
Ford F-150Chafed harness at the alternator bracket
BMW

P0123 su BMW 3-Series

2001-2011

E46 M54 and E90 N52 often log P0123 when the DK-Motor (throttle actuator) potentiometer starts failing. Genuine throttle bodies run €450-600 for parts alone, aftermarket VDO units around €250.

Cosa causa P0123 su una BMW 3-Series?

BMW 3-SeriesDK-Motor potentiometer wear on high-mileage cars
BMW 3-SeriesPedal position sensor harness chafe at the firewall grommet

Costo di riparazione di P0123 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 TPS connector, apply dielectric grease €0–€21 €0–€84 €0–€105 Facile
Replace standalone throttle position sensor (cable throttle) €56–€252 €56–€168 €112–€420 Facile
Replace complete electronic throttle body (drive-by-wire) €252–€910 €112–€308 €364–€1218 Moderata
Repair TPS wiring harness (short or open circuit) €28–€126 €126–€364 €154–€490 Moderata
PCM replacement and reprogram €700–€1960 €210–€490 €910–€2450 Professionale

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

Toyota

P0123 su Toyota Camry

2002-2011

2AZ-FE and 2GR-FE ETCS-i throttle bodies (22030-28070 / 22030-31010) rarely fail early, but when P0123 appears the internal sensor is usually the culprit. Idle relearn required after cleaning or replacement.

Cosa causa P0123 su una Toyota Camry?

Toyota CamryETCS-i throttle body internal sensor failure
Toyota CamryLoose or corroded battery ground strap causing false high reference

Costo di riparazione di P0123 per Toyota Camry

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

Riparazione Costo dei ricambi Costo della manodopera Stima totale Difficoltà fai-da-te
Clean and reseat TPS connector, apply dielectric grease €0–€14 €0–€54 €0–€68 Facile
Replace standalone throttle position sensor (cable throttle) €36–€162 €36–€108 €72–€270 Facile
Replace complete electronic throttle body (drive-by-wire) €162–€585 €72–€198 €234–€783 Moderata
Repair TPS wiring harness (short or open circuit) €18–€81 €81–€234 €99–€315 Moderata
PCM replacement and reprogram €450–€1260 €135–€315 €585–€1575 Professionale

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

Honda

P0123 su Honda Civic

2006-2015

8th/9th gen R18 engines occasionally log P0123 after aftermarket intake installs that disturb the throttle body connector. Honda's idle relearn (throttle body cleaned, KOEO 10 min with A/C off) is required after any TPS work.

Cosa causa P0123 su una Honda Civic?

Honda CivicDisturbed throttle body connector after intake or air box mods
Honda CivicMissed idle relearn after battery disconnect or throttle body service

Costo di riparazione di P0123 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 TPS connector, apply dielectric grease €0–€13 €0–€51 €0–€64 Facile
Replace standalone throttle position sensor (cable throttle) €34–€153 €34–€102 €68–€255 Facile
Replace complete electronic throttle body (drive-by-wire) €153–€553 €68–€187 €221–€740 Moderata
Repair TPS wiring harness (short or open circuit) €17–€77 €77–€221 €94–€298 Moderata
PCM replacement and reprogram €425–€1190 €128–€298 €553–€1488 Professionale

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

Questi codici compaiono spesso insieme a P0123 o indicano problemi correlati:

P0122P0121P0221P0222P2135

Domande frequenti su P0123

Will P0123 clear itself if I just drive it?

No. It's a hard electrical fault. The MIL might go out after several drive cycles without the fault recurring, but the underlying wiring or sensor issue almost always comes back within minutes.

Will P0123 make my car fail an emissions inspection?

Yes. It's a stored powertrain code with the MIL on, which is an automatic fail at any OBD2 inspection.

Do I need a new throttle body or just the sensor?

On older cable-throttle cars (mostly pre-2005) the TPS is a bolt-on €40-80 part. On drive-by-wire systems the sensor is integrated into the throttle body and you replace the whole assembly.

Why did my car go into limp mode with this code?

The PCM can't trust the throttle signal, so it ignores the pedal and holds the throttle at a fixed low opening (usually 1200-1500 RPM) to prevent unintended acceleration.

Do I need to relearn the throttle after replacing it?

Yes, on nearly all drive-by-wire cars. Most brands need a specific idle/throttle relearn procedure (Toyota, Honda, VW, BMW all have their own). Skipping this leaves rough idle even after a good part is fitted.

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