Kohler Command PRO ECH630 Service Manual page 42

Section 5
EFI Fuel System
Mounted on the thrott le body and operated directly
off the end of the thrott le shaft , the TPS works as a
potentiometer, varying the voltage signal to the ECU
in direct correlation to the angle of the thrott le plate.
This signal, along with the other sensor signals, is
processed by the ECU and compared to the internal
preprogrammed maps to determine the required fuel
and ignition sett ings for the amount of load.
The correct position of the TPS is established and
set at the factory. Do not loosen the TPS or alter the
mounting position unless absolutely required by fault
code diagnosis. If the TPS is loosened or repositioned,
the appropriate TPS Learn Procedure must be
performed to re-establish the baseline relationship
between the ECU and the TPS.
Figure 5-5. TPS Location.
Service
The TPS is a sealed, non-serviceable assembly.
If diagnosis indicates a bad sensor, complete
replacement is necessary. If a blink code indicates a
problem with the TPS, it can be tested as follows:
1. Counting the number of turns, back out the idle
speed adjusting screw (counterclockwise) until
the thrott le plates can be closed completely. Write
this number down for reference later.
2. Disconnect the Black connector from the ECU,
but leave the TPS mounted to the thrott le body.
3. a. Use an ohmmeter and connect the red
(positive) ohmmeter lead to Black pin 12
terminal and the black (negative) ohmmeter
lead to Black pin 10 terminal to test.
b. Hold the thrott le closed and check the
resistance. It should be 1400-1800 Ω.
5.10
4. Leave the leads connected to the pin terminals as
described in step 3. Rotate the thrott le shaft
slowly to the full thrott le position. Monitor the
dial during rotation for indication of any
momentary short or open circuits. Note the
resistance at the full thrott le position. It should be
4600-5200 without a stop pin, or 3200-4100 Ω
with a stop pin.
5. Disconnect the main wiring harness connector
from the TPS, leaving the TPS assembled to the
thrott le body. Refer to the following chart and
perform the resistance checks indicated between
the terminals in the TPS switch, with the thrott le
in the positions specifi ed. Pin location shown in
Figure 5-4.
Thrott le Between
Position Terminal
Closed A & C
Full with Stop
A & C
Pin
Full without
A & C
Stop Pin
Any A & B
If the resistance values in steps 3, 4, and 5 are
within specifi cations, go to step 6.
If the resistance values are not within
specifi cations, or a momentary short or open
circuit was detected during rotation (step 4), the
TPS needs to be replaced, go to step 7.
6. Check the TPS circuits (input, ground) between
the TPS plug and the main harness connector for
continuity, damage, etc. The input pin is 12 and
the ground is pin 10.
a. Repair or replace as required.
b. Turn the idle speed screw back in to its
original sett ing.
c. Reconnect connector plugs, start engine and
retest system operation.
7. Remove the two mounting screws from the TPS.
Save the screws for reuse. Remove and discard
the faulty TPS. Install the replacement TPS and
secure with the original mounting screws.
a. Reconnect the Black and TPS connector plugs.
b. Perform the TPS Learn Procedure integrating
the new sensor to the ECU.
Resistance
Continuity
Value (Ω)
1400-1800 Yes
3200-4100 Yes
4600-5200 Yes
3000-7000 Yes