Caterpillar Engine Monitoring

TM 9-2320-312-24-2

Troubleshooting Section

Caterpillar Engine Monitoring

Low coolant level will signal the ECM to limit the

maximum vehicle speed and the ECM will reduce

the engine power rating. Refer to Illustration 5.

"Off" Operation

This option is not applicable for OCT01 software.

If Caterpillar Engine Monitoring is programmed

to "OFF", the ECM will not flag high coolant

temperature or high inlet manifold air temperature.

No warnings will occur even though conditions

that could cause the ECM to take action (engine

monitoring) are exceeded.

The ECM still uses the sensors for engine operation.

The coolant temperature sensor is still used for

cold mode operation, control of the air inlet heater,

and control of the cooling fan. The inlet manifold

temperature is still used for operation in cold air,

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control of the air inlet heater, and control of the

Illustration 5

cooling fan. The coolant level is not used even if a

Graph for the coolant level

coolant level sensor is installed.

Derate mode is limited. (10% per second)

"WARNING" Operation

Very low oil pressure will signal the ECM to limit the

maximum vehicle speed and the ECM will reduce

If Caterpillar Engine Monitoring is programmed to

the engine power rating. Refer to Illustration 6.

"WARNING", the ECM will illuminate the Warning

lamp and the ECM will flash the Check Engine

lamp because of the active diagnostic code. The

flashing lamp indicates that a problem has been

detected by the engine monitoring system. The

diagnostic code is logged. No further action by the

ECM or action by the engine occurs if the ECM is

programmed to "WARNING".

"DERATE" Operation

If the system is programmed to "DERATE", the

ECM begins by flashing the Check Engine lamp

and the Warning lamp. The flashing lamps indicate

that a problem has been detected by the engine

monitoring system. The diagnostic code is logged.

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Illustration 6

High coolant temperature will signal the ECM to

Graph for very low oil pressure

limit the maximum vehicle speed and the ECM will

reduce the engine power rating. Refer to Illustration

This derating of engine performance is provided in

4 and Illustration 6.

order to get the driver's attention so the driver can

take action in order to avoid engine damage.

"SHUTDOWN" Operation

If the system is programmed to "SHUTDOWN", the

ECM takes all the action that is indicated for the

"DERATE" mode and the ECM will eventually shut

down the engine under some conditions.

The "SHUTDOWN" mode begins when any of the

following conditions exist:

"Very low oil pressure"

"Very low coolant level"

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Illustration 4

Coolant temperature bargraph

"Very high coolant temperature"

Derate mode is limited. (10% per second)