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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 22 (Engine Controls And Fuel - 2.8L (LWN) Diesel - Diagnostic Information And Procedures (2 Of 3)) >> Diagnostic Information and Procedures >> DTC P0658 or P0659 >> Circuit/System Description

Circuit/System Description

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Circuit Description
Ignition Regulated voltage supplied by the control module.
Signal The control module input circuit has an internal resistance connected to 5 V.
Ground Chassis Ground
Component Description
B75C Multifunction Intake Air Sensor The assembly has several functions :
  • The mass air flow sensor is a hot film type sensor that measures the mass of air (not the volume) entering the engine. The signal varies with engine load and is displayed by the scan tool in Hertz (Hz) and grams per second (g/s).
  • The intake air humidity sensor uses the same signal circuit as the intake air temperature sensor 2. The intake air humidity sensor modulates the pulse width of the signal. The intake air temperature sensor 2 modulates the frequency of the signal. That means the signal is both, PWM and FM modulated.
  • The barometric pressure sensor generates an analog voltage that is proportional to the ambient air pressure.
  • The intake air temperature sensor 1 varies its resistance depending on the temperature.
    • Low temperature produces a high resistance : 1, 166 ohms @ 40°C (104°F)
    • High temperature produces a low resistance : 97 ohms @ 130°C (266°F)