TM 9-2320-363-20-1
Section 3
TESTING THE DDEC III SYSTEM
A. TOOLS NEEDED TO DIAGNOSE THE SYSTEM
The following tools and equipment are required to properly diagnose a complete system:
MPSI - PROLINK Diagnostic Data Reader - J38500-750 (cartridge 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
terminals for circuit checking.
TRS/SRS Alignment Tool: J-39815 (Not needed on Series 60).
020" Feeler Gauge
In addition, the tools listed below can be of aid in properly identifying problems, but are not required for this
Troubleshooting Guide:
Kent Moore Vehicle Interface Test Module - J41005.
Tachometer: Either a crankshaft harmonic balance revolution pickup type or electronic coil trigger signal pickup type
tachometer can be used for diagnosis.
Pressure Gauge: To monitor turbo boost pressure (for purposes of comparison with the DDEC III Turbo Boost
Sensor).
B. DIFFERENCES BETWEEN DDEC III AND DDEC II
To those thoroughly familiar with DDEC II, an outline Is given of the differences in DDEC IIIl. From an installation and
testing viewpoint, these differences are:
DDEC fault codes are still able to be "flashed", but with DDEC III, a diagnostic request switch must be 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
developed 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 4 of this Troubleshooting Guide.
Fault codes are now referred to as active, and inactive.
DDEC IIIl requires injector calibrations to be entered into the EEPROM with the DDR. DDEC Ill 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 Ill engines are equipped with a 36 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). ' X Refer to code 85 page 3-345.395 for details.
Engine calibrations and software levels can be programmed via DDEC IIIl programming stations.
3-345.14 Change 3
