RV Safety Systems Drafted 7/5/10 Data from:
www.busconversions.com DDEC II and SilverLeaf (subject revised to reflect content)
DDEC II Information
1) On a DDEC II engine, you will need to look at PID 244 for the odometer reading.
2) On some early DDEC II there is no odometer data. It appears that DDEC II versions prior to about 1992-93 have this issue.
3) Detroit Diesel has a PROM upgrade that will upgrade to the final version of the DDEC II software version (154). The previous version was 141, which might work as well. The upgrade contains a new PROM that goes inside the ECM and a kit to hold it down. The part number for this is R6171618 and costs about $127 with a $40 core charge. It comes up as a PROM stabilizer kit, but it actually contains the new PROM as well.
4) Report from poster on BCM: “I bought and installed the R6171618 part, which is a PROM and a triangular shaped holder that bolts the PROM down to the circuit board in the ECM. This PROM updates the software to the last release of the DDEC II software which is 154. This software version makes the odometer part work properly with the VMS.”
5) Detroit Diesel dealer should have the PROM . If not, it can be ordered from: Diesel Parts Direct. Search for part number: R6171618. As noted above, it shows up as a “Stabilizer Kit”

From Jim Shepherd - RV Safety Systems