Test Step 1. Use Cat ET to Check for an Active Coolant Level Sensor Fault

188

TM 9-2320-312-24-2

Troubleshooting Section

Note: If the coolant level sensor is programmed to

The coolant level sensor is an OEM installed

"NO", the coolant level sensor is ignored by the

component for the vehicle. This sensor is an optional

ECM. Conversely, if the parameter is set, then a

sensor for "Engine Monitoring". "Engine Monitoring"

sensor must be installed. The "Engine Monitoring"

is a programmable feature of the Caterpillar ECM.

is set when the "Engine Monitoring" is programmed

The sensor is selectable through a Customer

to "WARNING", "DERATE", or "SHUTDOWN". The

Programmable Parameter and the Customer

"Coolant Level Sensor" is set when the coolant level

Programmable Parameter may be protected by

sensor is programmed to "4-Pin". If both parameters

Customer Passwords. Some OEM installed coolant

are set and a sensor is not installed, 111-02 Coolant

level sensors are not connected to the Engine

Level Sensor Fault (12) will be logged.

Control Module (ECM). Do not confuse an OEM

installed coolant level sensor that is independent of

2-Wire Float Sensor

"Engine Monitoring" with the coolant level sensor

that is used for "Engine Monitoring".

Applications that program the parameter

"Manufacturer/Model" to "Other" have the option of

The customer programmable parameter for the

using a 2-wire float sensor to monitor the coolant

coolant level sensor can be programmed to "4-Pin",

level. To use a 2-wire float sensor, the parameter

"2-pin switch", or "2-wire float sensor". Also, the

"Manufacturer/Model" must be programmed to

customer programmable parameter for the coolant

"Other" and the parameter "Coolant Level Sensor"

level sensor can be programmed to "NO" if the

must be programmed to "2-wire float sensor". The

option for the coolant level sensor is not being used.

sensor is connected to P1/J1:26 (sensor input)

and to P1/J1:5 (AP sensor/switch sensor common).

If the parameter "Coolant Level Sensor" is

The sensor will provide information to the ECM at

programmed to "NO", the coolant level sensor is

P1/J1:26 that will enable the ECM to determine if

ignored by the ECM. Conversely, if the parameter is

the coolant level is normal, low, or extremely low.

set, then a sensor must be installed. The "Engine

Monitoring" is set when the "Engine Monitoring"

The "Engine Monitoring" is set when the "Engine

is programmed to "WARNING", "DERATE", or

Monitoring" is programmed to "WARNING",

"SHUTDOWN". The coolant level is monitored by

"DERATE", or "SHUTDOWN". The "Coolant Level

the Engine Monitoring System when the parameter

Sensor" is set when the coolant level sensor

"Coolant Level Sensor" is programmed to "4-Pin"

is programmed to "2-wire float sensor". If both

or "2-wire float sensor".

parameters are set and a sensor is not installed,

111-02 Coolant Level Sensor Fault (12) will be

4-Pin Sensor

logged.

The sensor indicates the presence or the absence

2-Pin Switch

of coolant at the sensor probe. A sensor with a

4-pin connector that requires a +5 VDC connection

Note: Do not use this procedure to troubleshoot

to a power supply must be used. The sensor is

the 2-pin switch coolant level switch. Refer to

powered from the ECM through the ECM vehicle

Troubleshooting, "111-01 Low Coolant Level

harness connector J1/P1 terminal 2 (+5 VDC). The

Warning" or Troubleshooting, "111-11 Very Low

ECM vehicle harness connector has 70 terminals.

Coolant Level" for the proper troubleshooting

The signal wires for the coolant level sensor are

procedure.

connected at J1/P1:54 (coolant level low) and at

J1/P1:49 (coolant level normal). The common wire

Test Step 1. Use Cat ET to Check for an

for the sensor is connected to the ECM vehicle

Active Coolant Level Sensor Fault

harness connector J1/P1 through terminal 5 (AP

sensor/switch sensor common).

A. Connect Caterpillar Electronic Technician (Cat

If coolant is present at the sensor probe, J1/P1:54

ET) to the cab data link connector.

(coolant level low) has an output of near 0 VDC. If

coolant is present at the sensor probe, J1/P1:49

B. Turn the ignition key switch to the ON position.

(coolant level normal) has an output near +5 VDC. If

coolant is not present at the sensor probe, J1/P1:54

C. Access the active diagnostic screen on Cat ET.

(coolant level low) has an output of near +5 VDC. If

coolant is not present at the sensor probe, J1/P1:49

D. Verify that one of the following diagnostic codes

(coolant level normal) has an output of near 0 VDC.

is active:

111-02 Coolant Level Sensor Fault (12)

111-03 Coolant Level Sensor Open Circuit (12)