Turbo and forced inductionGeneric OBD-II codeUrgency: Garage soon
Code P0237: turbo pressure sensor: low signal
P0237 means: turbocharger boost pressure sensor "A": circuit low.[1][2] The ECU receives from the boost pressure sensor "A", the one that measures the pressure the turbo generates, a signal lower than corresponds to its normal operation. TaT describes it as a possible electrical problem in the circuit: a short to ground, a faulty sensor or a wiring or connector fault.[1][2]
What code P0237 means
The ECU receives from the boost pressure sensor "A", the one that measures the pressure the turbo generates, a signal lower than corresponds to its normal operation. TaT describes it as a possible electrical problem in the circuit: a short to ground, a faulty sensor or a wiring or connector fault.[1][2]
In Saab's manual for the 9-5 with the 2010 2.0 turbo engine, the code is stored when the sensor voltage drops below 0.19 V for more than 4 seconds in a row (or 50 seconds cumulatively). The ECU then disables pressure control and leaves only the turbo's mechanical pressure, with a marked drop in power.[3]
Ross-Tech shows it on Volkswagen Group cars as a signal that is too low from the manifold and boost pressure sensor (G31), with two possible causes: the sensor's electrical supply or the sensor itself. On the 1.4 petrol engines it cites (North American version), it warns that it may appear together with P0106 and that it is worth keeping the ECU software up to date.[4]
It is a generic OBD-II code (it starts with P0), so its definition is the same on any make; what changes from one engine to another is the most likely cause.[5]
Original definition (SAE J2012): Turbocharger Boost Sensor A Circuit Low[1][2]
Causes of P0237
From most to least likely, according to the sources.
- 1Faulty boost pressure (MAP) sensor.[1][2][3][4][6]
- 2Sensor wiring and connectors in poor condition: damaged or corroded wires, loose or faulty connections, a short circuit (for example, to ground) or an open circuit.[1][2][3][6]
- 3Faulty 5 V supply or reference earth for the sensor.[3][4]
- 4Faulty vacuum hoses on the sensor.[1]
- 5Faulty intake air temperature sensor, according to CarWiki; on the Saab 9-5 it is integrated with the pressure sensor in a single four-circuit part.[3][6]
- 6Intake system leaks, faulty turbo or intercooler and a clogged air filter: Autodoc includes them in its list without explaining how they would produce a low signal. For the A3 2.0 CR TDI, Ross-Tech cites a technical bulletin on the failure of an intercooler hose.[1][4]
- 7Faulty engine ECU, or one with out-of-date software.[1][3][4]
Symptoms
- Engine warning light on in the instrument cluster.[4][6]Engine warning light: faults that cause it
- Noticeable loss of power, especially with the engine under load.[1][3][6]Less power: faults that cause it
- The ECU disables pressure control and leaves the engine with only the turbo's mechanical pressure, or the engine goes into limp mode.[3][6]Limp mode: faults that cause it
- Poor acceleration and delayed response when pressing the accelerator.[1][6]
- Rough idle or engine hesitation.[1]Vibrations: faults that cause it
- Noticeably higher fuel consumption.[1]Uses more fuel: faults that cause it
- Black or bluish smoke from the exhaust.[1]Black smoke: faults that cause it
- Hard starting or an engine that stalls after starting.[1][6]Hard to start: faults that cause it
How to diagnose P0237
In order: from the most likely and cheapest to check to the most expensive.
- 1Read all stored codes and check in particular that there are no codes for the sensors' 5 V supply (in Saab's manual, P0641, P0642 and P0643): if there are, they are dealt with first.[3]
- 2Visually check the connectors and wiring of the pressure sensor (and of the air temperature sensor, if integrated): loose or corroded connections, damaged wires.[1][3][6]
- 3With the sensor disconnected, measure at the connector the 5 V supply (Saab's manual gives between 4.8 and 5.2 V with the ignition on) and the reference earth (less than 5 Ω). Ross-Tech includes the sensor's supply among its checks.[3][4]
- 4Check the signal as per Saab's manual: with the sensor disconnected, the scan tool reading should be high (more than 275 kPa) and, when you bridge the signal and the reference earth with a jumper, drop to almost zero (less than 1 kPa). This distinguishes a wiring problem from a sensor one; the values are for that engine, so look up those for yours.[3]
- 5Inspect the sensor's vacuum hoses, the hoses and the intercooler and the whole intake for leaks (Saab's manual suggests soapy water in a spray bottle), and check the air filter.[1][3]
- 6On Volkswagen Group cars, check the ECU software version and consult the manufacturer's technical bulletins: Ross-Tech cites several, for example for the 2.0 TDI-PPD (earth points, wiring loom of the pressure and air temperature sensors, software update) and for the 1.4 petrol engines.[4]
- 7Replace the sensor only if the circuits are fine; if not, repair the wiring or check the ECU.[1][3]
Can I keep driving with P0237?
Garage soon
The sources do not fully agree. Autodoc Club allows short trips, asks for the car to be repaired quickly and advises avoiding high revs and full-throttle acceleration, because the engine can be damaged if the turbo receives incorrect pressure values. Mechanic Base, in its article on the boost pressure sensor, states that you should never drive with it faulty. In Saab's manual, the ECU limits the engine to the turbo's mechanical pressure, with a noticeable loss of power.[1][3][7]
Documented faults related to P0237
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 P0237?
Only short distances, gently and as far as the workshop. Autodoc Club recommends repairing the car quickly and avoiding high revs and full-throttle acceleration, and Mechanic Base states that you should never drive with a faulty boost pressure sensor. In Saab's manual, power drops because the ECU stops regulating pressure electronically.[1][3][7]
What is the difference between P0237 and P0238?
They are opposites: P0237 indicates a sensor signal that is too low and P0238 one that is too high. In Saab's manual, P0237 is set below 0.19 V and P0238 above 4.85 V, for more than 4 seconds in a row (or 50 seconds cumulatively), and the ECU's response is the same: disable pressure control and leave only the turbo's mechanical pressure.[2][3]
Does P0237 mean the turbo is producing little pressure?
Not necessarily. P0237 is a sensor code: TaT describes it as a low sensor signal, with electrical causes such as a short to ground, a faulty sensor or wiring and connector problems. Genuinely insufficient boost pressure has its own code, P0299, which KFZ Dietrich describes as a pressure below what is expected.[2][8]
How do I tell whether the sensor or the wiring is at fault?
With the sensor disconnected, you measure the reference earth, the 5 V supply and the signal at the connector, and check how the scan tool reading reacts when the signal is bridged to the reference earth. Only if the circuits are fine is the sensor tested or replaced; Ross-Tech says to check the sensor's supply first.[3][4]
Does P0237 mean the same on all makes?
The definition is the same, because codes that start with P0 are generic OBD-II codes, but each manufacturer displays it with its own wording: Ross-Tech describes it on the Volkswagen Group as a signal that is too low from the manifold and boost pressure sensor (G31), and Saab's manual speaks of a voltage that is too low from the boost pressure sensor.[3][4][5]
Will I pass the MOT with code P0237?
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.[9]
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 P0237: causas, síntomas y cómo corregirloAutodoc Club · Technical documentation · consulted 2 October 2026 · in Spanish
- P0237 — Turbocharger Boost Sensor A Circuit LowThe Automotive Technician (TaT) · Technical documentation · consulted 2 October 2026
- DTC P0236, P0237, or P0238 (LDK with Turbocharger) 9-5 (9650) 2010Saab Workshop Information System (WIS Online) (copia del manual de taller de Saab) · Technical documentation · consulted 2 October 2026
- 16621/P0237/000567 - Manifold Pressure / Boost Sensor (G31): Signal too LowRoss-Tech Wiki · Technical documentation · consulted 2 October 2026
- On-board diagnosticsWikipedia · Other source · consulted 2 October 2026
- OBD Fehlercode P0237 | TurboladerladedrucksensorCarWiki.de · Technical documentation · consulted 2 October 2026 · in German
- 3 Signs Of A Bad Or Failing Boost Pressure SensorMechanic Base · Other source · published 19 February 2023 · consulted 2 October 2026
- P0299 vs. P0234 vs. P0245: Resultat oder Stellglied?KFZ Dietrich · Other source · published 4 August 2026 · consulted 2 October 2026 · in German
- 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