Faulty boost pressure sensor (MAP sensor or dedicated sensor); Damaged, disconnected, or corroded electrical connector at the sensor; Open or shorted wire in the sensor signal or reference circuit; Poor ground connection for the sensor circuit; Intake air leaks or restrictions upstream of the sensor; Failed powertrain control module (rare); Aftermarket modifications or incorrect sensor installed

DTC codes / P02xx · Fuel and air metering (injector circuits) / P0235

P0235Turbocharger Boost Sensor A Circuit Malfunction

Q: What does code P0235 mean?

Turbocharger Boost Sensor A Circuit Malfunction. P0235 is a generic powertrain code indicating that the powertrain control module has detected an abnormal condition in the electrical circuit for Turbocharger Boost Sensor A, which is typically the manifold absolute pressure sensor or a dedicated boost pressure sensor. The computer monitors the sensor's signal voltage and sets this code when the reading falls outside the expected range for the current engine operating conditions, often indicating an open circuit, short circuit, or sensor failure.

P0235 is a generic powertrain code indicating that the powertrain control module has detected an abnormal condition in the electrical circuit for Turbocharger Boost Sensor A, which is typically the manifold absolute pressure sensor or a dedicated boost pressure sensor. The computer monitors the sensor's signal voltage and sets this code when the reading falls outside the expected range for the current engine operating conditions, often indicating an open circuit, short circuit, or sensor failure.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Reduced engine power or limp mode, especially during acceleration
Poor fuel economy or rich-running condition
Hesitation, stumble, or lack of boost when accelerating
Rough idle or unstable engine operation
In some cases, the engine may enter a default boost strategy, limiting turbocharger output

Common causes, most likely first

Faulty boost pressure sensor (MAP sensor or dedicated sensor)
Damaged, disconnected, or corroded electrical connector at the sensor
Open or shorted wire in the sensor signal or reference circuit
Poor ground connection for the sensor circuit
Intake air leaks or restrictions upstream of the sensor
Failed powertrain control module (rare)
Aftermarket modifications or incorrect sensor installed

How to diagnose and fix it

Perform a visual inspection of the sensor and its wiring harness for obvious damage, corrosion, or loose connections
Check for technical service bulletins (TSBs) or known issues for the specific vehicle make and model
Use a scan tool to read live data and compare boost sensor readings with expected values under key-on, engine-off and running conditions
Measure reference voltage and signal voltage at the sensor connector with a digital multimeter, verifying against manufacturer specifications
Check continuity and resistance of the signal, reference, and ground circuits between the sensor and the PCM
Test the sensor with a hand vacuum pump or pressure source while monitoring scan tool data to confirm proper response
Replace the boost sensor if electrical tests confirm it is faulty, then clear codes and verify repair with a road test

What the boost sensor code hides

A P0235 can be set by a simple loose connector that looks fine at a glance, so always wiggle-test the harness while watching live data.
Many technicians replace the boost sensor only to find the real problem is a chafed wire in the harness near the engine mount or exhaust heat shield.
This code does not always mean the sensor is bad; a faulty ground or reference voltage from the PCM can mimic a sensor failure.
Intake leaks after the turbocharger can cause the sensor to read abnormally, setting P0235 without any sensor electrical fault.
On some vehicles, the boost sensor is integrated into the MAP sensor, so a P0235 may be accompanied by MAP-related codes and misdiagnosed as a MAP failure.

Can I keep driving with P0235?

You can usually drive the vehicle with P0235, but expect reduced performance and possible limp mode; avoid heavy acceleration or towing until the fault is repaired, as the engine may not manage boost correctly.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.