Camshaft Speed/Timing Sensor

TM 9-2320-312-24-2

Troubleshooting Section

Coolant Temperature Sensor This sensor detects

Camshaft Speed/Timing Sensor This sensor

the engine coolant temperature for Cold Mode

provides a variable amplitude and PWM signal to

operation and the Caterpillar Engine Monitoring. The

the ECM. The ECM interprets this signal as the

Caterpillar Engine Monitoring must be programmed

crankshaft position and the engine speed.

in the ON position for the coolant temperature

sensor to be effective.

CAT Data Link The data link is an electrical

connection that is used to communicate with other

Cooling Fan Cab Override Switch This switch

microprocessor based devices. The microprocessor

overrides control of the cooling fan relay so the

based devices are compatible with the proposed

cooling fan operates continuously. This switch is

American Trucking Association and the SAE

supplied and installed by the OEM.

Standard. These devices include trip recorders,

electronic dashboards, and maintenance systems.

Cooling Fan Relay This relay is controlled by

The data link is also the communication medium

the ECM which uses information from the coolant

that is used for programming with the Caterpillar

temperature sensor, the engine retarder and the

Electronic Technician (ET ). The data link is also

air conditioning high pressure switch. The air

used for troubleshooting with ET .

conditioning high pressure switch is not always

installed. The relay and the air conditioning high

Caterpillar Driver Information Display (CAT ID)

pressure switch is supplied and installed by the

The Caterpillar Driver Information Display is a

OEM.

digital readout of the performance parameters of

the vehicle and performance parameters that are

Cruise Control Range The cruise control range

monitored by the ECM.

is the speed range that is monitored by the cruise

control. This speed range is typically the anticipated

Caterpillar Engine Monitoring Caterpillar Engine

speed range on the open road. The cruise control

Monitoring is the part of the Caterpillar electronic

range is programmable by using the low cruise limit

engine control that monitors coolant temperature, oil

and the high cruise limit.

pressure, inlet manifold air temperature and coolant

level. The monitoring alerts the operator of detected

Custom Data Custom data is part of the fleet trip

problems. Coolant temperature, intake manifold air

data that is stored in the ECM. This capability allows

temperature, and oil pressure sensors are supplied

the vehicle owner to specify operating parameters

by Caterpillar and monitored by the ECM. The

for monitoring purposes while the engine is in

coolant level sensor is installed by the vehicle

service.

OEM but still monitored by the ECM. Aftermarket

engine monitoring systems do not interface with the

Customer Specified Parameter A customer

Caterpillar Electronic Engine Control.

specified parameter is a value that can be set and

changed by the customer. The parameters can be

Check Engine Lamp The check engine lamp is

protected by customer passwords.

sometimes referred to as the diagnostic lamp. The

check engine lamp is used to alert the operator of

Data Link Refer to the ATA Data Link and J1939

the presence of an active event. The lamp then

Data Link.

flashes a diagnostic code.

Desired RPM The desired rpm is input to the

Clutch Pedal Position Switch The switch is

electronic governor within the ECM. The electronic

typically supplied and installed by the OEM. This

governor uses the signal from the accelerator pedal

switch is typically a limit switch that is mounted near

position sensor, the engine speed sensor, the cruise

the clutch pedal. The switch is usually adjustable.

control, and the customer parameters in order to

This switch is in the normally closed position when

determine desired rpm.

the clutch pedal is released. Depressing the clutch

pedal will open the circuit.

Diagnostic Event Code These codes indicate an

event that describes an abnormal engine condition

Code Refer to the Diagnostic Fault Code and the

such as an idle shutdown occurrence. These codes

Diagnostic Event Code.

are not necessarily an indication of problems within

the electronic system.

Cold Mode Cold Mode is a mode for cold starting

and for cold engine operation that includes timing

Diagnostic Fault Code A diagnostic fault code is

that is retarded and low idle that is raised. This

sometimes referred to as a fault code. These codes

mode is used for engine protection, reduced smoke

indicate an electronic system malfunction.

emissions and faster warm up time.

Diagnostic Flash Code The diagnostic flash codes

Coolant Level Sensor This OEM installed sensor

are flashed on the check engine lamp. These flash

detects the absence or presence of coolant at the

codes indicate a malfunction in the electronic

probe. The sensor then sends a signal to the ECM.

system or an event that is detected by the ECM.