GxT Ferret 63 DIAGNOSTIC ENGINE ANALYZER - Manual (Page 11)

THROTTLE POSITION SENSOR
This is a computer aided test to check for skips in a
position sensor signal sweep. When a position sensor
on a throttle or air flow vane is moved from the rest posi-
tion to the top, the output voltage should move just like
the position shaft. The voltmeter reading for this test
updates rapidly so that small irregularities are not likely
to be missed.
Press START.
Then connect Auxiliary Clip to the output wire and press
START.
Using the following voltmeter display, check that the out-
put responds to a typical range of 1 to 4 volts when the
position sensor shaft is turned.
In the TP Sensor test the analyzer detects abrupt voltage
changes that an intermittent sensor contact would make.
Be ready to smoothly turn or press the position sensor
through its full sweep. Press START.
With the "DETECT ON" display, make a smoothly in-
creasing sweep during 3 to 7 seconds to the top posi-
tion. The test ends automatically when the voltage stops
changing. Findings are reported when the test ends.
If glitches were detected, the corresponding voltage lev-
els will be reported. Recheck the sensor for intermittent
faults near the reported problem voltages.
If no irregularities were detected it will show:
If the test was run too fast or slow it will show:
SELECT : POSITION SENSOR
TEST then START
CONNECT Aux to TP Sensor
Engine OFF; Key ON
0.84 v
for test: Press START
DETECT ON 0.84 v
Move SLOWLY to W.O.T
WIGGLE SCOPE
The Wiggle Scope display can be selected to see a line
trace of slow or intermittent voltage changes. It has a 10
megohm input impedance.
This display is like a chart recorder that is written at the
left of the screen and flows off the right end. It shows
voltage levels and changes above or below 4 volts
sensed by the Auxiliary Clip.
Level changes during an interval are shown different
ways: an / or \ shows a simple change, a T or its inverse
means there was a change but the start and end were
the same, ||| shows that there were many changes.
SELECT: WIGGLE SCOPE
TEST then START
Wiggle Scope can be used to watch for regular or inter-
mittent pulses on wires for accessories, sensors, lamps,
solenoids, slow computer codes, or other on/off electrical
signals. The shortest step is about 1/10th second on the
fastest scan.
The number following "SCAN" is the time for the signal
to sweep across the display. SELECT can choose a 2,
4, 8 or 16 second sweep.
-9-
Possible Problem 1.93v
Press START
No GLITCHES Found;
Press START
Too FAST; Retest Slower
Too SLOW; Retest Faster
WIGGLE SCOPE Scan 2 Sec
ˇˇ/\|/T\/__\/-----------