DDEC DIAGNOSTIC CODE
Troubleshooting of the DDEC III system and the DDEC IV system is identical. At the time of this
printing, the available features are the same in both systems. The DDEC IV system allows for an
increased processor speed and increased memory. DDEC III ECMs and DDEC IV ECMs are
A diagnostic code indicates a problem in a given circuit (i.e. diagnostic Code 14 indicates
a problem in the oil or coolant temperature sensor circuit). This includes the oil or coolant
temperature sensor, connector, harness, and Electronic Control Module (ECM). The procedure
for finding the problem can be found in Flash Code 14, refer to section 14.3. Similar sections
are provided for each code. Remember, diagnosis should always begin at the start of the section.
For an oil or coolant temperature sensor problem, it will quickly lead you to section 14, but
first you verify the code or symptom.
Since the self-diagnostics do not detect all possible faults, the absence of a code does not mean
there are not problems in the system. If a DDEC problem is suspected, even in the absence of a
code, refer to section 9.1, anyway. This section can lead you to other sections that can aid in the
troubleshooting process - where DDEC problems may occur, but do not generate a code. Basic
mechanical checks are not covered in this manual.
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION