Ch. 26

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Ford Throtlle Posilion (TP) Sensor Chart
Throttle Angle (Degrees)
Voltage (V)
0 0.50
10 0.97
20
1 lA
30 1.90
40 2.37
50 2.84
60 .t.J I
70 3.78
BO 4.24
Testing the Tlerm'&tfre
Fosition Semser
A TP sensor can be tested using one or more of the
following tools:
x A digital voltmeter with three test leads connected
in series between the sensor and the wiring
harness connector or backprobing using T-pins.
€ A scan tool or a specific tool recommended by the
vehicle manufacturer.
tr Abreakout box that is connected in series
between the computer and the wiring harness
connector(s). A typical breakout box includes test
points at which TP voltages can be measured
with a digital voltmeter.
ffi An oscilloscope.
i::!;41ii:re* ?**E E A meter lead connected to a T-pin that
was gently pushed along the signal wire of the TP sensor
until the point of the pin touched the metal terminal inside
the olastic connector.
A 1V nC I :1 PRS8E B 2S0mV tlFF 1 r l PRilBE
200msrBIV $IN&LE f.igrAJ -3nIU
Use jumper wires, T-pins, or a breakout box to
gain electrical access to the wiring to the TP sensor.
See Figure 26-17.
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The procedure that follows is the usual 1
method ,rsed by many manufacturers. Always refer to I
serrice literature for the exact tecommended procedure I
, .and specifications for the vehicle bein9 fested,
I
The procedure fol testing the sensor using a digital
multimeter is as follos's:
I". Turn the ignition ss'itch on rengine offl.
2. Measure the voltage benr-een the signai wire
and ground (reference ios- s-ire. The r-oltage
should be about 0.5 volt.
' Consult the service literature for exact rvire
colors or locations.
3. \\-ith the engine still not running (but ivith the
igmtion sti11 on ), slowly increase the thlottle
FREE I*PTURE l,lil{ ltlAH
EUH 10 milIV on A
TRIGGER
at 5t3X
Fig:irre ?#"*i? A typical waveform of a TP sensor signal as
recorded on a DSO when the accelerator pedal was
depressed with the ignition switch on (engine off). Clean
transitions and the lacl< of any glitches in this waveform
indicate a good sensor. (Courtesy of Fluke Corporation)
opening. The voltage signal from the TP sensor
should also increase. Look for any "dead spots" or
open circuit readings as the throttle is increased
to the wide-open position. See Figure 26-12 for
an example of how a good TP sensor would look
u'hen tested rvith a digital storage oscilloscope
(DSO).