Turbo Compressor Inlet Temperature Signal Low
What does DD-1172-4 mean?
The DD-1172-4 (Detroit Diesel DD Series) diesel fault code means: Turbo Compressor Inlet Temperature Signal Low. This is a minor severity code.
Common Symptoms
- Check Engine Light / Amber Warning Lamp illuminated
Probable Causes (Ranked by Likelihood)
- Shorted signal Likely
- Failed sensor Likely
Step-by-Step Diagnostic Procedure
Back-probe sensor.
Replace sensor.
Frequently Asked Questions
What is Detroit Diesel fault code DD-1172-4?
Detroit Diesel fault DD-1172-4 (SPN 1172 FMI 4) indicates: Turbo Compressor Inlet Temperature Signal 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-1172-4?
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-1172-4?
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.