Engine (Oil) Temperature Sensor; Intake Air Temperature Sensor; Manifold Absolute Pressure Sensor (Map); Temperature/Manifold Absolute Pressure (Tmap) Sensor - Kohler command pro ECH749 Service Manual

EFI SYSTEM-ECH

Engine (Oil) Temperature Sensor

A sealed, non-serviceable assembly. A faulty sensor
must be replaced. If a blink code indicates a problem
with temperature sensor, it can be tested as follows:
1. Remove temperature sensor from breather cover
and cap or block sensor hole.
2. Wipe sensor clean and allow it to reach room
temperature (25°C, 77°F).
3. Unplug Black connector from ECU.
4. With sensor still connected, check temperature
sensor circuit resistance between Black pin 10 and
14 terminals. Value should be 9000-11000 Ω.
5. Unplug sensor from wire harness and check sensor
resistance separately across two pins. Resistance
value should again be 9000-11000 Ω.
a. If resistance is out of specifi cations, replace
temperature sensor.
b. If it is within specifi cations, proceed to Step 6.
6. Check circuits (input, ground), from wire harness
connector to sensor plug for continuity, damage, etc.
Connect one ohmmeter lead to Black pin 14 in wire
harness connector (as in step 4). Connect other lead
to terminal #1 in sensor plug. Continuity should be
indicated. Repeat test between Black pin 10 and
terminal #2 in sensor plug.
Earlier engines have a separate intake air
temperature (IAT) sensor (located in throttle body)
and a manifold absolute pressure (MAP) sensor
(located in intake manifold).

Intake Air Temperature Sensor

A non-serviceable component. Complete replacement is
required if it is faulty. Sensor and wiring harness can be
checked as follows.
1. Remove temperature sensor from throttle body.
2. Allow it to reach room temperature (20°C, 68°F).
3. Unplug Black connector from ECU.
4. With sensor still connected, check temperature
sensor circuit resistance between Black pin 10 and 8
pin terminals. Value should be 3100-3900 Ω.
5. Unplug sensor from wire harness and check sensor
resistance separately across two pins. Resistance
value should again be 3100-3900 Ω.
a. If resistance is out of specifi cations, replace
temperature sensor.
b. If it is within specifi cations, proceed to Step 6.
6. Check circuits (input, ground), from main harness
connector to sensor plug for continuity, damage, etc.
Connect one ohmmeter lead to Black pin 8 in main
harness connector (as in step 4). Connect other lead
to terminal #1 in sensor plug. Continuity should be
indicated. Repeat test between Black pin 10 and
terminal #2 in sensor plug.
42

Manifold Absolute Pressure Sensor (MAP)

A sealed, non-serviceable assembly. A faulty sensor
must be replaced. If a blink code indicates a problem
with manifold absolute pressure sensor, it can be tested
as follows:
1. Make sure all connections are making proper
contact and are free of dirt and debris. Remove
blower housing. Slide locking tab out and pull off
manifold absolute pressure connector. Turn key
switch to ON and check with a volt meter by
contacting red lead to pin 1 and black lead to pin 2.
There should be 5 volts present, indicating ECU and
wiring harness are functioning.
2. Check continuity in wire harness. Ohms between Pin
3 at sensor connector and Black pin 11 connector at
ECU should be near zero ohms. If no continuity is
measured or very high resistance, replace wire
harness.
3. Check to make sure intake manifold is not loose and
MAP sensor is not loose. Loose parts would allow a
vacuum leak, making MAP sensor report misleading
information to ECU.
a. Tighten all hardware and perform an ECU Reset
and a TPS Learn Procedure to see if MIL will
display a fault with MAP sensor again. If MIL fi nds
a fault with MAP sensor, replace it.
Later engines have a combined temperature/
manifold absolute pressure (TMAP) sensor (located
in intake manifold).
Temperature/Manifold Absolute Pressure (TMAP)
Sensor
A sealed non-serviceable integrated sensor that checks
both intake air temperature and manifold absolute
pressure. Complete replacement is required if it is faulty.
Sensor and wiring harness can be checked as follows.
If a blink code indicates a problem with Intake Air
Temperature (TMAP) Sensor Circuit (P0112 or P0113), it
can be tested as follows:
1. Remove TMAP sensor from intake manifold.
2. Allow it to reach room temperature (20°C, 68°F).
3. Unplug Black connector from ECU.
4. With sensor still connected, check temperature
sensor circuit resistance between Black pin 10 and 8
pin terminals. Value should be 1850-2450 Ω.
5. Unplug sensor from wire harness and check sensor
resistance separately across pin. Resistance value
should again be 1850-2450 Ω.
a. If resistance is out of specifi cations, check local
temperature. Sensor resistance will go down as
temperature is higher. Replace TMAP sensor if
determined to be faulty.
b. If it is within specifi cations, proceed to Step 6.
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