4
4.33
THROTTLE POSITION SENSOR (TPS)
OPERATION OVERVIEW
Mounted on the throttle body and operated directly off
the end of the throttle shaft, the TPS works like a
rheostat, varying the voltage signal to the ECU in direct
correlation to the angle of the throttle plate. This signal is
processed by the ECU and compared to the internal pre-
programmed “maps” to determine the required fuel and
ignition settings for the amount of engine load.
IMPORTANT
The correct position of the throttle body stop screw is
established and set at the factory.
DO NOT remove the tamper proof cap to adjust the
throttle body stop screw or alter its position in any
manner.
The stop screw controls the air flow calibration of the
throttle body.
TPS RESISTANCE TESTS
The TPS is a non-serviceable item. If it is faulty, it must
be replaced. It can be tested with a Ohm meter using the
following method:
With the test leads connected and the meter set to read
Ohms, compare the resistance readings with those given
in the tables.
NOTE
Resistance readings may vary slightly from vehicle to
vehicle. The important thing to remember when testing
the TPS is to look for a smooth, uninterrupted sweep
between closed and open throttle. Sweep can also be
checked using Digital Wrench® diagnostic software.
TPS RESISTANCE READINGS
PINS
THROTTLE
POSITION
RESISTANCE
2 — 3
Closed to Open
1000 - 5000 Ω ± 1kΩ
Resistance value
should change
smoothly as throttle is
opened and closed.
2 — 1
Closed to Open
5000 - 1000Ω ± 1kΩ
Resistance value
should change
smoothly as throttle is
opened and closed.
1 — 3
Open or Closed
5000Ω ± 40%
NOTE: Reading does
not change with
throttle position
FUEL SYSTEM
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