
RENR9348-01 109
Troubleshooting Section
Results:
•
OK – The resistance check indicates that
continuity exists.
Repair: Perform the following procedure:
1. Connect the J1
/P1 connectors. Connect Cat ET
to the service tool connector.
2. Check the Cat D
ata Link for proper operation. If
the Data Link does not operate correctly, there
may be a problem with the ECM.
Replace the ECM. Refer to Troubleshooting,
“Replacing the ECM” for information that is
related to EC
Mreplacement.
STOP.
•
Not OK – The resistance check did not indicate
that continuity exists in the circuit. There is an open
circuit or ex
cessive resistance in the harness.
Repair: There may be a problem with a connector.
Repair the w
iring and/or the connectors. Replace
parts, if necessary.
STOP.
i02410638
Coolant Lev
el Sensor Circuit
-Test
SMCS Code: 1
439-038-CLT
System Operation Description:
Use this procedure to troubleshoot any suspect
problems with the circuit for the coolant level sensor.
The coolant level sensor monitors the engine coolant
level in order to warn the operator in the event that
the coolan
t level is low. The coolant level sensor is
located on the expansion tank.
g01150024
Illustration 30
Coolant level sensor
(1) Sensor
(2) Sensor probe (brass d owel)
(3) Plastic cover
Coolant level sensor (1) contains no moving parts.
The sensor provides the same function as a
switch. The state of the switch is dependent on the
capacitance value that is detected at the probe of
the sensor. The sensor contains a probe (2) that is
covered with plastic (3).
When the sensor’s probe is immersed in coolant, the
sensor senses a particular capacitance. The sensor’s
electronics react by sinking the signal to the digital
return (ground).
When the probe is not immersed in coolant,
approximately +5 VDC is sourced to the signal wire.
When this condition is detected by the Electronic
Control Module (ECM), an event code is activated.
Prior to troubleshooting any problems with the
coolant level sensor, use Caterpillar Electronic
Technician (ET) to check the installation status for
the sensor. The coolant level sensor’s configuration
parameter must be set to “Installed” in order for the
ECM to monitor the signal from the sensor.
The activation of an event code and/or a warning
lamp is probably caused by a low coolant level. The
next likely cause is a problem with the wiring harness,
a connector, or the sensor. The least likely cause is
a problem with the ECM.