P0235 - TURBOCHARGER BOOST SENSOR WITH CIRCUIT MALFUNCTION

The MAP (Manifold Absolute Pressure) sensor creates pressure through the turbocharger, which changes according to the position of the throttle and the engine speed. The ECM (Engine Control Module) uses this information to help diagnose the BARO (Barometric Pressure) sensor and protect against engine overpressure.

The MAP sensor is composed of a low reference circuit, a signal circuit, and a 5-volt reference circuit. On the other hand, the engine control module gives a 5-volt reference and at the same time distributes ground in a low reference circuit. The MAP sensor sends a signal to the ECM indicating any pressure changes, and the ECM checks this signal as soon as the voltage drops below normal. The ECM compares the value obtained to the actual signal.

• The check engine light is on.
• The engine may lose acceleration, or have a general power failure.
• Noisy sounds or vibrations in the turbocharger or its pipes.

A P0235 code can be caused by one of these faults:

• There may be a vacuum leak in the intake manifold.
• The air purifier could be dirty.
• The discharge valve may be defective or stuck open.
• Some obstruction in the oil supply or return line.
• Vibration in the turbocharger bearings
• Maybe some connection in the intake pipe to the throttle body is loose.
• Poor electrical connection to the turbo pressure sensor.
• Short circuit between the sensor cables and the ECM.

To solve the DTC code P235, you can check the following components:

• Make sure the engine works properly, without misfiring.
• With the engine cold, check the hoses and their respective turbo clamps.
• You can check the manifold and verify that there are no leaks.
• Start the engine and at idle it should have between 16 and 22 inches of vacuum, if it does not exceed 16 it indicates that the catalytic converter might be defective.
• Revolve the engine quickly to 5000 RPM, then release the throttle and with a vacuum pressure gauge, observe if the boost pressure rises above 19 pounds of impulse, if so, this indicates that there is a poor gas output. If not, that means that the boost stops rising between 14 and 19 pounds, it means that the problem could be in the turbo.
• With the engine cold, remove the turbo hose and check that the blades are not sticking from the sides, as well as that they are not bent or missing.
• Make sure there is no oil leakage between the engine block and the turbo support unit.
• Using a voltmeter, locate the 5-volt reference from the ECM to the sensor and confirm that the reference voltage exists. If it shows that there is no voltage, it could indicate that there is a short circuit in the cable system or even that the ECM (Engine Control Module) is defective.