Diagnostic Lamp

TM 9-2320-312-24-2

Troubleshooting Section

2 The data is erratic, intermittent, or incorrect.

Diagnostic Lamp A diagnostic lamp is sometimes

called the check engine light. The diagnostic lamp

3 The voltage is above normal or the voltage is

is used to warn the operator of the presence of an

active diagnostic code.

shorted high

4 The voltage is below normal or the voltage is

Direct Current (DC) Direct current is the type of

current that flows consistently in only one direction.

shorted low

5 The current is below normal or the circuit is

Dual Coil Vehicle Speed Sensor The dual coil

vehicle speed sensor is a magnetic pickup that

open

senses movement of the teeth on the output shaft

6 The current is above normal or the circuit is

of the transmission. The sensor contains two coils.

One of the coils supplies a signal to the vehicle

grounded

speedometer, and the other coil is a vehicle speed

7 The mechanical system is not responding

buffer.

properly

Duty Cycle Refer to Pulse Width Modulation.

8 Abnormal frequency, pulse width, or period

Electronic Control Analyzer Programmer (ECAP)

9 Abnormal update

The ECAP is an electronic service tool that was

replaced by the CAT Electronic Technician.

10 Abnormal rate of change

Electronic Engine Control The electronic engine

11 The failure mode is not identifiable

control is a complete electronic system. The

electronic engine control monitors the engine

12 Damaged device or component

operation under all conditions. The electronic

engine control also controls the engine operation

13 The device or the component is not calibrated

under all conditions.

14 and 15 These locations are reserved for a

Electronic Technician (CAT ET ) The ET is a

service tool that uses a software program in order

future assignment

to run on a personal computer (PC). This program

replaced the ECAP tool.

Flash Code (FC) The flash codes are proprietary

Caterpillar code numbers that are flashed on the

Engine Control Module (ECM) The ECM is the

diagnostic lamp.

engine's control computer. The ECM provides power

to the electronics. The ECM monitors data that is

Flash Programming Flash programming is the

input from the engine's sensors. The ECM acts as a

method of programming or updating an ECM

governor in order to control engine rpm.

with ET over the data link instead of replacing

components.

Estimated Dynamic Timing The estimated dynamic

timing is the estimate that is provided by the ECM

Fleet Information Software (FIS) FIS is a software

of the actual injection timing.

program that operates on a PC. This program

allows the user to review the trip information.

Exhaust Brake Relay The brake solenoids are

The program also allows the user to reset the

driven by an OEM installed relay, which is driven

trip information which includes the "Maintenance

by the ECM.

Indicator" information.

Failure Mode Identifier (FMI) This identifier

Fuel Position This is an internal signal within

indicates the type of failure that has been

the ECM. The signal comes from the electronic

experienced by the component. The FMI has

governor and the signal then goes to the fuel

been adopted from the SAE practice of J1587

injection control. The information that is gathered is

diagnostics. The descriptions for the diagnostic

based on the desired rpm, the FRC limit, the rated

codes are shown in the following list:

fuel limit, and the actual engine rpm.

0 The data is valid but the data is above the

Fuel Ratio Control (FRC) The FRC is a limit that

is based on the control of the fuel to air ratio. The

normal operational range

FRC is used for purposes of emission control. When

1 The data is valid but the data is below the

the ECM senses a higher boost pressure (more air

into the cylinder), the FRC increases the FRC limit

normal operational range

(more fuel into the cylinder).