BOOST PRESSURE SENSOR
DESCRIPTION
The boost pressure/intake air temperature sensor is
mounted to the top of the intake manifold. The sensor
allows the ECM to monitor air pressure within the
intake manifold. This sensor is also used to monitor
the intake air temperature.
OPERATION
When the intake manifold pressure is low sensor voltage output is 0.25-1.8 volts at the ECM. When the intake
manifold pressure is high due to turbo boost, sensor voltage output is 2.0-4.7 volts. The sensor receives a 5-volts
reference from the ECM. Sensor ground is also provides by the ECM. The ECM uses boost pressure combined with
intake air temerature to determine the volume of air entering the engine.
DIAGNOSIS AND TESTING - BOOST PRESSURE/INTAKE AIR TEMPERATURE
SENSOR
If the boost pressure sensor fails, the ECM records a DTC into memory and continues to operate the engine in one
of the three limp-in modes. When the ECM is operating in this mode, a loss of power will be present, as if the
turbocharger was not operating. The best method for diagnosing faults with the boost pressure sensor is with the
scan tool. Refer to the Diesel Powertrain Diagnostic Manual for more information.
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FUEL INJECTION - 2.8L DIESEL
KJ