Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Charge Pressure Sensor
Overview
The boost pressure sensor is a combined sensor and contains two sensors in the same component:
- air pressure sensor
- temperature sensor.
The boost pressure sensor is located on the upper part of the charge-air cooler.
Air pressure sensor
The air pressure sensor detects the pressure in the intake manifold downstream of the charge-air cooler (CAC). The signal from the sensor is primarily used by the Engine Control Module (ECM) to check that the correct boost pressure is reached. The boost pressure is governed by the turbocharger control valve.
The sensor, which is a piezo resistor, is grounded in the control module and supplied with 5 V from the control module.
Depending on the pressure in the intake manifold, the resistance changes in the sensor, which gives a signal between 0.5 - 4.5 V.
Low pressure gives low voltage, high pressure gives high voltage.
The air pressure sensor can be diagnosed by the Engine Control Module (ECM), and the sensor signal can be read off using the diagnostics tool.
Temperature sensor
The temperature sensor detects the temperature on the inlet air after the charge-air cooler.
The information is used by Engine Control Module (ECM) to calculate boost pressure control, as well as for calculating injection time. The control module also controls certain diagnostic functions using the temperature sensor's signal.
The sensor, which is an NTC resistor, is grounded in the control module and supplied with power (signal) from the control module.
Depending on the temperature in the inlet air's temperature, the resistance changes in the sensor, which gives a signal between 0.5 - 5 V to the control module.
Low temperature gives high voltage (high resistance), high temperature gives low voltage (low resistance).
The Engine Control Module (ECM) can diagnose the temperature sensor. The sensor signal can be read using the diagnostic tool.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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