Turbo and forced inductionGeneric OBD-II codeUrgency: Garage soon
Code P0235: turbo pressure sensor circuit fault
P0235 means: turbocharger boost pressure sensor "A": circuit malfunction.[1][2][3] The control unit has detected a fault in the circuit of boost pressure sensor "A", which measures the pressure the turbo generates and reports it to the control unit. With an unreliable reading, the turbo can be regulated badly and the engine delivers less power than normal and responds worse when you accelerate.[1][3]
What code P0235 means
The control unit has detected a fault in the circuit of boost pressure sensor "A", which measures the pressure the turbo generates and reports it to the control unit. With an unreliable reading, the turbo can be regulated badly and the engine delivers less power than normal and responds worse when you accelerate.[1][3]
It is worth knowing that this code is used in two ways. By definition it points to the sensor circuit, but some manufacturers, such as the Volkswagen group, display it as "boost pressure: control range not reached". That is why the lists of causes mix the sensor and its wiring with the wastegate, the hoses and the turbo.[1][4][5]
It is a generic OBD-II code (it starts with P0), so its definition is the same on every make; what changes from one engine to another is the most likely cause.[6]
Original definition (SAE J2012): Turbocharger Boost Sensor A Circuit Malfunction[1][2][3]
Causes of P0235
From most to least likely, according to the sources.
- 1Faulty wastegate or its actuator, or faulty pressure control solenoid valve (the N75 on VAG cars).[1][2][4][5]
- 2Faulty boost pressure sensor (MAP sensor).[1][2][5]
- 3Vacuum or pressure hoses to the turbo that are damaged, blocked, badly connected or leaking.[1][2][4]
- 4Loose, corroded or deteriorated sensor wiring or connectors.[1][2][5]
- 5Leaks in the intake duct or the intercooler.[1][2]
- 6Turbo with mechanical damage or a faulty control unit.[1][2][4]
- 7Dirty or faulty mass airflow sensor, or blocked air filter.[1][2]
- 8Faulty engine control unit, a cause the sources leave until last.[1][2][5]
Symptoms
- Loss of power, especially when accelerating.[1][2][4][5]Less power: faults that cause it
- The engine goes into limp mode, with limited power.[1][2][4][5]Limp mode: faults that cause it
- Engine warning light on in the dashboard.[5]Engine warning light: faults that cause it
- Delayed or weak response when you press the accelerator.[1][2][5]
- Whistling or hissing in the engine bay.[1][2]Turbo whistle: faults that cause it
- Black smoke from the exhaust, especially with the engine under load.[1][2]Black smoke: faults that cause it
- Higher fuel consumption than usual.[1][2]Uses more fuel: faults that cause it
How to diagnose P0235
In order: from the most likely and cheapest to check to the most expensive.
- 1Start with the simplest things: visually check the connectors and wiring of the pressure sensor and the turbo regulator, looking for loose, rusty or damaged connections.[1][2][5]
- 2Inspect the vacuum and pressure hoses going to the turbo, the intake duct and the intercooler: cracks, hardening, blockages or leaks.[1][2][4]
- 3Check the air filter and clean or replace the mass airflow sensor if it is dirty.[1][2]
- 4Check the pressure regulation: the control solenoid valve (the N75 on VAG cars), the wastegate actuator and its vacuum supply.[1][4]
- 5Check the pressure sensor with the diagnostic tool (and with an oscilloscope or multimeter if needed) and replace it only after checking its electrical connections and its power supply.[1][2][5]
- 6Only if everything above is fine, check the turbo and, last of all, the control unit.[1][2][4]
Can I keep driving with P0235?
Garage soon
You can cover short distances with the car in limp mode, but the code should be corrected as soon as possible: driving for a long time with the turbo not working properly can seriously damage the engine.[1][2]
Parts related to code P0235
The parts that most often cause this code. The code points to the circuit, not always the part: diagnose before you buy.
Affiliate links: if you buy from these shops, MotorFiable may receive a commission at no cost to you. Check compatibility against the registration plate or VIN before ordering. More information
Documented faults related to P0235
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Engine sensors: the most serious faults by engine and car
- High severityFrequency: Occasional2.0 DTI and 2.2 DTIVP44 injection pump and air mass meter failureGerman Wikipedia documents recurring failures of the Bosch VP44 injection pump and the air mass meter in the early years of this engine. An owner testimony for this engine describes the pump being replaced at 192,500 km, at a cost the owner calls «prohibitive».
- Medium severityFrequency: Common2.0 TDIClogged particulate filter or faulty pressure sensorThe 2.0 TDI's particulate filter clogs if the car mostly makes short journeys, because it never gets to regenerate; sometimes the fault is just the differential pressure sensor. Cleaning it costs around €200 and replacing it, €800 to €3,000.Repair (garage): €800–€3,000
- Medium severityFrequency: Common1.4 and 1.6 8vCrankshaft position sensor failure (TDC sensor)The crankshaft position sensor (capteur PMH, or TDC sensor) appears repeatedly in the reliability sources for the Clio II, the Kangoo I and the Dacia Logan I with this engine, with hard cold starting or stalling as the main symptoms. It is a cheap part, but the failure can leave you stranded.
- Medium severityFrequency: Common1.4 and 1.6 16vCrankshaft position sensor failureThe crankshaft position sensor (capteur PMH) appears repeatedly in the reliability sources for almost every generation with this engine, with hard cold starting, stalling or the car cutting out unexpectedly. It is a cheap part, but the failure can leave you stranded.
Turbo: the most serious faults by engine and car
- High severityFrequency: Very frequent1.6 HDiTurbo failure through lack of lubrication (carbon deposits and union filter)On the 16-valve 1.6 HDi/TDCi engines (2004-2011) the turbo can seize because carbon deposits from the oil clog the mesh filter in the union that feeds it. It is a serious, repeat fault: if only the turbo is replaced without cleaning the circuit, it fails again.Repair (garage): €700–€1,050
- High severityFrequency: Very frequent2.0 Ingenium diéselTurbocharger failureYes: according to several sources, the turbo is the component that causes the most faults on the 2.0 Ingenium diesel. It fails across a very wide mileage range (from around 35,000 to over 140,000 km) and, if it breaks up inside, it can send oil or metal into the engine and destroy it.Repair (garage): €2,600–€3,000Appears at around 35,000 km
- High severityFrequency: CommonBMW N47Turbo and wastegate valve failureThe N47's turbo does not usually fail from general wear, but because of failure of the wastegate valve, which regulates boost and can seize or lose adjustment, sending fuel consumption soaring; oil leaks from the turbo itself are also common.Repair (garage): €900–€1,800
- High severityFrequency: CommonOM651Variable-geometry turbo failure and its pneumatic actuatorThe OM651's variable-geometry turbo tends to fail at the pneumatic actuator (cracks, loss of calibration) before the turbo itself. Symptoms range from a gradual loss of power to permanent limp mode, with whistling or smoke if the problem progresses.Repair (garage): €500–€3,000
Wiring, connectors and short circuits: the most serious faults by engine and car
- Critical severityFrequency: OccasionalBMW N62 / N63Additional turbo coolant pump with a risk of short circuit and fireIn 2011 BMW recalled 5, 6 and 7 Series, X5 and X6 models built between 2007 and 2011 because of the additional turbo coolant pump: moisture, a short circuit and, in extreme cases, a fire. In 2012 there was another campaign for a crack in the pump, with a more robust version.
- Critical severityFrequency: Occasional1.6 GDi híbrido (Kappa)Main relay of the power relay assembly (overheating and fire risk)Yes, on the first units: Hyundai and Kia recalled 2016–2018 Ioniq and Niro hybrids and plug-in hybrids because the main relay that connects the high-voltage battery could come loose, overheat and, in the worst case, cause a fire.
- Critical severityFrequency: Occasional1.6 GDi híbrido (Kappa)Clutch hydraulic actuator (HCA): leak or moisture with risk of short circuit and fireYes, this is the most documented hybrid system fault: the hydraulic actuator that engages the combustion engine with the hybrid assembly has had two recalls (2018 for a leak on the Niro and 2025 for moisture in its electronic board on the Niro, Ceed and XCeed PHEV), with a risk of short circuit and fire.
- High severityFrequency: Occasional1.3 TCeBlown fuel pump fuseOn the Renault Captur II and Clio V with the 1.3 TCe engine, a 20-amp fuse can blow and leave the car without an engine. According to L'argus, in April 2021 this fault still had no factory fix; the official service centre's diagnosis includes checking, and sometimes replacing, the catalytic converter.
- Critical severityFrequency: CommonRover 75Seat SRS connector fault with airbag and seatbelt warning light onAuto Express warns that the Rover 75's seat SRS connector can cause the airbags to fail, and dealers were fixing it with revised connectors. The Dutch APK inspection puts the airbag or seatbelt fault warning among the most frequent defects across almost all series.
- Critical severityFrequency: OccasionalAlfa Romeo GiuliettaShort circuit from badly routed wiring that can prevent gear shifting (KBA campaign, 2010-2015)Yes: according to Germany's KBA, on Alfa Romeo Giulietta cars built between 2010 and 2015 inadequate cable routing could cause a short circuit and, as a result, gear-shift failure.
Frequently asked questions
Can I drive with code P0235?
Only short distances, gently and straight to a garage. The sources warn that prolonged driving can seriously damage the engine.[1][2]
Does P0235 mean the sensor is broken?
Not necessarily. By definition it points to the sensor circuit, but the lists of causes also include the wastegate, the hoses and pipes, leaks, the air filter, the mass airflow sensor and the turbo, and the Volkswagen group displays it as a pressure control range not reached.[1][2][3][4]
How is P0235 diagnosed?
With a systematic check: wiring and connectors, hoses and leaks, air filter and mass airflow sensor, pressure regulation (solenoid valve and actuator), sensor and, at the end, the turbo and the control unit.[1][2][4][5]
Does P0235 mean the same on every make?
The official definition is the same on all of them, because codes starting with P0 are generic OBD-II codes, but each manufacturer may describe the fault with its own wording, as the Volkswagen group does.[4][6]
Will I pass the MOT with code P0235?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[7]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- Código OBD2 P0235: causas, síntomas y cómo corregirloAutodoc Club · Technical documentation · consulted 2 October 2026 · in Spanish
- OBD2 code P0235: causes, symptoms & how to fix itAutodoc Club · Technical documentation · consulted 2 October 2026
- P0235 — Turbocharger Boost Sensor A Circuit MalfunctionThe Automotive Technician (TaT) · Technical documentation · consulted 2 October 2026
- 16619/P0235/000565: Boost Pressure: Regulation Range not ReachedRoss-Tech · Technical documentation · consulted 2 October 2026
- OBD Fehlercode P0235 | Turboladerladesensor | Renault, Audi, Ford & Co.CarWiki.de · Technical documentation · consulted 2 October 2026 · in German
- On-board diagnosticsWikipedia · Other source · consulted 2 October 2026
- Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish