DEF Tank Temperature High
What does DD-1673-0 mean?
The DD-1673-0 (Detroit Diesel DD Series) diesel fault code means: DEF Tank Temperature High. This is a minor severity code.
Common Symptoms
- Check Engine Light / Amber Warning Lamp illuminated
- DEF heater runaway
Probable Causes (Ranked by Likelihood)
- Failed DEF tank temp sensor Likely
- Heater stuck on Possible
Step-by-Step Diagnostic Procedure
Measure DEF tank temp; should be 40-200F.
Replace header assembly if stuck heater.
Frequently Asked Questions
What is Detroit Diesel fault code DD-1673-0?
Detroit Diesel fault DD-1673-0 (SPN 1673 FMI 0) indicates: DEF Tank Temperature High. It is a minor-severity fault and is commonly seen on DD13/DD15/DD16 engines in Freightliner and Western Star chassis.
Can I drive my Freightliner or Western Star with fault DD-1673-0?
It depends on severity. Critical and serious faults trigger derate or engine shutdown — do not continue driving. Moderate faults usually allow continued operation short-term but schedule repair to prevent cascading aftertreatment damage.
How much does it cost to fix Detroit Diesel fault DD-1673-0?
Typical repair cost is $200-$900. Sensor/harness fixes fall at the low end; turbo actuator, injector, aftertreatment component, or head gasket repairs fall at the high end. Detroit DDDL software and sometimes factory parameter reset are required for proper reset.