TOOLS NEEDED TO DIAGNOSE THE SYSTEM

TM 9-2320-364-20-1

Section III. TESTING THE DDEC III/lV SYSTEM

A. TOOLS NEEDED TO DIAGNOSE THE SYSTEM

The following tools and equipment are required to properly diagnose a complete system:

MPSI -- PRO-LINK Diagnostic Data Reader (DDR) -- J38500-750 (cartridge only) (DDEC ll/lll only).

Multi-protocol cartridge P/N 208040 and Smartcard P/N 802115 (DDEC lll/lV only).

Voltmeter and Ohmmeter: Use a digital volt-ohmmeter J-34029 or equivalent to measure voltage and resistance where

required. A digital volt-ohmmeter must be used when specified in a procedure.

Test Light 6V: Must be used when specified in the procedure.

Jumper Wires: To bypass a circuit and to insert between special connectors. This will permit access to the connector termi-

nals for circuit checking.

TRS/SRS Alignment Tool: J-39815.

.020" Feeler Gauge

Crankshaft Position Timing Tool: J34930-A

B. DIFFERENCES BETWEEN DDEC III/lV AND DDEC II

To those thoroughly familiar with DDEC II, an outline is given of the differences in DDEC III/lV. From an installation and testing

viewpoint, these differences are:

DDEC fault codes are still able to be "flashed", but with DDEC III/lV, a diagnostic request switch has been installed. There

are no longer provisions to use a jumper wire. The DDC assigned fault codes no longer appear on the "MPSI" diagnostic

data reader.

When using the MPSI DDR, the diagnostic codes are now displayed in a SAE J1587 format. The SAE have devel-

oped a standardized list of Parameter Identification Descriptions (PID), and a System Identification Description

(SID). These PIDs and SID will define the area where the fault has occurred. Following the PID or SID will be a

Failure Mode Identifier (FMI). The diagnostic codes (both DDEC and SAE) and their description can be found in

Section IV of this Troubleshooting Guide.

Fault codes are now referred to as active and inactive.

DDEC III/lV requires injector calibrations to be entered into the EEPROM with the DDR. DDEC III/lV uses this information

to provide proper cylinder balancing. Injector information must be programmed whenever an injector is replaced, or

changed for different cylinder location.

DDEC III/lV engines are equipped with a 36 tooth pulse wheel, instead of DDEC II's 13 tooth pulse wheel.

Added information now appears for some fault codes. This data includes: the hour the code is first logged, last logged,

number of occurrences, number of overrides (if applicable), and the value that caused the fault to be logged (if applicable).

Refer to code 85 page 2-759 for details.