DEF Tank Level Low
What does DD-1761-1 mean?
The DD-1761-1 (Detroit Diesel DD Series) diesel fault code means: DEF Tank Level Low. This is a minor severity code.
Common Symptoms
- DEF warning lamp with countdown
- DEF gauge at empty
Probable Causes (Ranked by Likelihood)
- DEF tank actually low — refill needed Very Likely
- Failed in-tank level sensor Likely
- Contaminated float / sensor sludge Possible
Step-by-Step Diagnostic Procedure
Visually verify DEF level in tank.
Refill with API-certified DEF and clear code.
If code returns with full tank, replace header assembly (contains level sensor).
Frequently Asked Questions
What is Detroit Diesel fault code DD-1761-1?
Detroit Diesel fault DD-1761-1 (SPN 1761 FMI 1) indicates: DEF Tank Level Low. 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-1761-1?
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-1761-1?
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.