Escape AWD V6-3.0L VIN 1 (2004)
Throttle Body: Description and Operation
Electronic Throttle Body (ETB)
ELECTRONIC THROTTLE BODY (ETB)
The Gen II electronic throttle body (Figure 133) has the following characteristics
1. The DC motor is driven by the PCM (requires two wires). The gear ratio from the motor to the throttle plate shaft is 17:1.
2. There are two designs; parallel and in-series. The parallel design has the motor under the bore parallel to the plate shaft. The motor housing is
integrated into the main housing (in general this is more difficult to package). The in-series design has a separate motor housing that protrudes out
and offers more packaging flexibility.
3. Two springs are used: one is used to close the throttle (main spring) and the other is in a plunger assembly that results in a default angle with no
power applied. This is for limp home reasons (force of plunger spring is 2 times stronger than the main spring). Default angle is usually set to
result in a top vehicle speed of 30 MPH (48 Km). Typically this throttle angle is 7 to 8 degrees from the hard-stop angle.
4. The closed throttle plate hard stop is used to avoid the throttle from binding in the bore (-0.75 degree). This hard stop setting is non-adjustable and
is set to result in less airflow than the minimum engine airflow required at idle.
5. Unlike cable type throttle bodies, the intent for the ETB is not to have a hole in the throttle plate or to use plate sealant. The hole is not required in
the ETB because the required idle airflow is provided by the plate angle in the throttle body assembly. This plate angle controls idle and idle
quality and eliminates the need for IAC bypass actuator.
6. The system has two throttle position sensors. Redundant throttle position signals are required for monitor reasons. TP1 has a negative slope
(increasing angle, decreasing voltage) and TP2 has a positive slope (increasing angle, increasing voltage). During normal operation the negative
sloped TP sensor (TP1) is used by the control strategy as the indication of throttle position. The TP sensor assembly requires four wires.
-
5 V Reference Voltage
-
Signal Return (ground)
-
TP1 voltage with negative voltage slope (5-0)
-
TP2 voltage with positive voltage slope (0-5)
