Engine Controls - 4.8L, 5.3L, & 6.0L (Introduction): Overhaul GMC Sierra 3500

Throttle Body Assembly

The throttle body assembly consists of the throttle body, the throttle position (TP) sensors, and the throttle actuator motor. The throttle body functions similar to a conventional throttle body with the following exceptions

1. An electric motor opens and closes the throttle valve.
2. The throttle blade is spring loaded in both directions and the default position is slightly open.
3. There are 2 individual TP sensors within the throttle body assembly.

The TP sensors 1 and 2 are potentiometer type sensors, each with the following circuits

1. A 5-volt reference circuit
2. A low reference circuit
3. A signal circuit

The TP sensors are used to determine the throttle plate angle. The control module provides each TP sensor a 5-volt reference circuit and a low reference circuit. The TP sensors then provide the control module with signal voltage proportional to throttle plate movement. Both TP sensor signal voltages are low at closed throttle and increase as the throttle opens.

Fuel Sender Assembly

The front fuel sender on dual tank applications consists of the following major components

1. The fuel level sensor
2. The fuel tank fuel pump module
3. The fuel strainer
4. The fuel filter

Scheme 46

The rear fuel sender on dual tank applications consists of the following major components

1. The fuel level sensor (4)
2. The FTP sensor (1)
3. The rear fuel pump (2)

Scheme 47

The fuel sender assembly on single tank applications consists of the following major components

1. The fuel level sensor
2. The fuel tank pressure (FTP) sensor
3. The fuel tank fuel pump module
4. The fuel strainer
5. The fuel filter