Kohler AEGIS LH630 Service Manual page 45

Mounted on the throttle body/intake manifold 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, along with the other sensor signals,
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 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 or throttle shaft service. If the TPS is
loosened or repositioned the "TPS Initialization
Procedure" (see pages 5B.7 and 5B.8) must be
performed to re-establish the baseline relationship
between the ECU and the TPS.
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
throttle plate can be closed completely.
2. Disconnect the main harness connector from the
ECU, but leave the TPS mounted to the throttle
body/manifold.
3. Connect the ohmmeter leads as follows:
(See chart on page 5B.24.) Connect the Red
(positive) ohmmeter lead to #8 pin terminal, and
the Black (negative) ohmmeter lead to #4 pin
terminal. Hold the throttle closed and check the
resistance. It should be 800-1200 Ω Ω Ω Ω Ω .
4. Leave the leads connected to the pin terminals as
described in step 3. Rotate the throttle shaft slowly
counterclockwise to the full throttle position.
Monitor the dial during rotation for indication of any
momentary short or open circuits. Note the
resistance at the full throttle position. It should be
1800-3000 Ω Ω Ω Ω Ω .
5. Disconnect the main wiring harness connector
from the TPS, leaving the TPS assembled to the
manifold. Refer to the following chart and perform
the resistance checks indicated between the
terminals in the TPS socket, with the throttle in the
positions specified.
www.SmallEngineDiscount.com
Throttle
Position
Closed
Closed
Full
Full
Any
If the resistance values in steps 3, 4, and 5 are
within specifications, go to step 6.
If the resistance values are not within
specifications, 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., Pin Circuits #8 and #4.
See chart on page 5B.24.
a. Repair or replace as required.
b. Turn the idle speed screw back in to its
c. Reconnect connector plugs, start engine and
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 both connector plugs.
b. Perform the "TPS Initialization Procedure"
TPS Initialization Procedure
"32 Pin" (MSE 1.1) Plastic-Cased ECU (Auto-Learn
Initialization)
1. Check that the basic engine, all sensors, fuel, fuel
pressure, and battery are good and functionally
within specifications.
Important!
2. Remove/disconnect ALL external loads from the
engine (belts, pumps, electric PTO clutch,
alternator, rectifier-regulator, etc.).
Not For Resale
EFI Fuel System
Between Resistance
Terminals Value (Ω)
2 & 3 800-1200
1 & 3 1800-3000
2 & 3 1800-3000
1 & 3 800-1200
1 & 2 1600-2500
original setting.
retest system operation.
integrating the new sensor to the ECU.
Section 5B
Continuity
Yes
Yes
Yes
Yes
Yes
5B
5B.7