4.17
FUEL INJECTION
4
THROTTLE POSITION SENSOR (TPS)
Operation Overview
The throttle position sensor (TPS) is used to indicate throttle
plate angle to the ECU.
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.
NOTE: The correct position of the TPS is
established and set at the factory. Do not loosen the
TPS or alter the mounting position. If the TPS is
repositioned, replaced or loosened it must be re-
calibrated.
TPS Test
The throttle position sensor (TPS) is a non-serviceable item. If
it is faulty, it must be replaced. It can be tested using the
following method:
NOTE: Before proceeding with any of the following
measurements or tests, it’s extremely important to
verify the throttle body bore is clean of any carbon
build-up. Remove the intake boot and inspect the
throttle body bore. If required, remove the throttle
body and clean the bore.
• Set up the TPS Test Adapter Harness (PU-47082),
according to the instructions that accompanied the
tester. Make sure that the 9 volt battery is new.
VERIFY TPS TESTER REFERENCE VOLTAGE
A 5 volt reference voltage from the harness is required for the
TPS test to be accurate. Refer to the instructions provided with
the TPS Test Adapter Harness (PU-47082) or follow the bullet
point steps to check reference voltage.
• Harness Test: Insert black voltmeter probe into the
“Bk” test port.
• Connect the red meter probe into the “R” port and
verify the voltage is 4.99-5.01 Vdc. If this reading is
low, verify the 9 volt battery is good or try a new 9 volt
battery.
Test Procedure
1. Plug the TPS test adaptor harness in the TPS harness.
2. Connect the red test probe in yellow test port and black test
probe in the black test port and the meter to VDC. Move
the throttle open and closed slowly while reading the
display. The voltage should increase smoothly with no
“jumps” or decreases when the throttle is applied.
PU-47082 TPS Test
Adapter Harness
Use NEW
9V battery
PU-47082 Harness
No “Jumps” in read out
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