EXPLANATION OF ABBREVIATIONS/TERMS -726280590

TM 9-2320-364-20-1

2-14. DDEC III/IV TROUBLESHOOTING (CONT).

Section II. BASIC KNOWLEDGE REQUIRED (Cont.)

D. EXPLANATION OF ABBREVIATIONS/TERMS

A/D

-- Analog to Digital: The computer inside the ECM uses an A/D converter to convert a sensor voltage into a

number which the computer can work with.

BAT

-- Battery

BOI

-- Beginning of Injection: The number of crank angle degrees, Before Top Dead Center, where the ECM is

requesting the injectors be turned on.

CAN

Controller Area Network: J1939 High speed control data link.

CEL

-- Check Engine Light: Typically mounted on the instrument panel. It has two functions:

1. It is used as a warning lamp to tell the operator of the vehicle that a fault has occurred and the unit should be

taken in for service as soon as possible.

2. It is used by the operator or technician to "flash" out inactive trouble codes to help diagnose a problem.

As a light bulb check and system check, the check engine light will come on for about 5 seconds when the ignition

is turned on. If the CEL remains on, or comes back on, the self diagnostic system has detected a problem. If the

problem goes away, the light will go out, but a trouble code will be stored in the ECM as an inactive code. ( general

diagnostic information, section II, E for details.)

CGL

-- Check Gauges Light: Typically mounted on the instrument panel. It has two functions:

1. It is used as a warning to the operator that a potential engine damaging condition has been detected.

2. It is used by the operator or technician to "flash" out active trouble codes.

As a light bulb check and system check, the "Check Gauges" light will come on for about 5 seconds when the

ignition is turned on.

CKT

-- Circuit

-- Crankshaft Position: An ECM output generated anytime an SRS signal occurs.

COM

-- Common

CTS

-- Coolant Temperature Sensor: Monitors coolant temperature.

DDEC II

-- Second generation Detroit Diesel Electronic Controls.

DDEC III -- Third generation Detroit Diesel Electronic Controls.

DDEC IV -- Fourth generation Detroit Diesel Electronic Controls.

DDL

-- Diagnostic Data Link: The lines (wires) over which the ECM transmits information which can be read by a

Diagnostic Data Reader.

DDL+

-- Data Link, Positive side: J1587 data link.

DDL--

-- Data Link, Negative side: J1587 data link.