Rick's Free Auto Repair Advice

Boost Pressure System Monitor

Boost Pressure System Monitor Operation

What is boost pressure on a diesel engine?

A boost pressure system (turbocharger) is used on diesel engines to increase the pressure produced inside the intake manifold to a level greater than atmospheric pressure. The pressure increase helps to ensure compete combustion of the air-fuel mixture.

Boost pressure along with more fuel produces more power

One way to get more power is to build a larger diesel. But that adds weight. So engineers instead use a turbocharger to push more air into the engine. The pressurized air being pumped in to the engine is called boost, with the pressure increase compared to ambient air pressure measured in PSI or bar/kilopascals.

How a boost pressure monitoring system works

The Boost Pressure System Monitor checks for component integrity and system operation, and tests for faults in the system.

The boost pressure sensor monitoring system measures the absolute image of manifold absolute pressure sensorpressure before the throttle valve (barometric pressure minus manifold vacuum). The engine control unit uses its signal to calculate a value for the boost pressure.

By detecting the amount of boost and air density in the car’s intake manifold, the ECU can determine how much fuel is needed in the car’s combustion chamber so that the air-fuel mixture is at its best.

The boost pressure system monitor tests the sensor and sets a fault code if it fails the test

The Boost Pressure System readiness Monitor is a “Two-Trip” Monitor. If a fault is found on the first trip, the computer temporarily saves the fault in its memory as a Pending Code. The computer does not command the MIL on at this time. If the fault is sensed again on the second trip, the computer commands the MIL “On,” and saves the code in its long-term memory.

©, 2022 Rick Muscoplat

Posted on by Rick Muscoplat

Custom Wordpress Website created by Wizzy Wig Web Design, Minneapolis MN