Cummins fault code 777
Turbocharger #1 Turbine Inlet Temperature High: reading above normal (most severe)
What it means
Cummins' description: Turbocharger #1 Turbine Inlet Temperature High - warning level.
SPN 1180 is Turbocharger #1 Turbine Inlet Temperature High. FMI 0 means the sensor is working, but the value it reports is far above where it should be. This is the most severe 'high' level.
The turbocharger forces air into the engine. Most modern Cummins engines use a variable geometry turbo (VGT) with an electronic actuator. The ECM watches intake manifold pressure, turbo speed and compressor temperatures to control boost.
What the lamp means
An amber (yellow) warning lamp means the engine can usually keep running, but the fault should be repaired soon, ideally the same day.
Green, yellow, red: three ways this can look
The same code can be a quick fix or a reason to shut down. Match your situation to the closest example.
Keep an eye on it
A brief underboost code climbing a hill that clears, with normal power the rest of the time.
Schedule a repair
Noticeable power loss, black smoke, or amber lamp with a boost or VGT code. Get it checked. Boost leaks and sticky VGT actuators get worse and hurt fuel economy.
Stop and get help
Loud whine or grinding from the turbo, heavy smoke, oil pouring out of the exhaust, or a stop lamp. Shut it down. A failing turbo can feed parts or oil into the engine.
Common causes
The sensor reading itself is out of range or the condition is real, so look at the system:
- Boost leak: split charge air hose, loose clamp, cracked charge air cooler
- VGT vanes sticking from soot
- Worn or damaged turbo
- Clogged air filter or intake restriction
- Exhaust restriction from a plugged DPF
What you can check before calling
- Listen for a new hiss or whistle under load, a typical sign of a boost leak
- Check charge air hoses and clamps for oil or soot
- Check the air filter restriction indicator
- Notice whether power loss happens only under heavy load or on hills
Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers.
Engines and sources
Cummins uses the same fault code numbers across its electronic engines, including on-highway models like the ISB/B6.7, ISL/L9 and ISX/X15, though not every code applies to every engine or software level. Source: Diagnostic Fault Codes for Cummins Engines. Always confirm with Cummins service information (QuickServe) for your engine serial number.
Related Turbo, VGT and boost codes
- 768 SPN 923 FMI 11
Output Device Driver (VGT or Transmission shift PWM signal): root cause not known - 743 SPN 1176 FMI 2
Turbocharger 1 Compressor Intake Pressure: erratic or intermittent signal - 742 SPN 1176 FMI 4
Turbocharger 1 Compressor Intake Pressure Circuit: circuit voltage low / shorted low - 741 SPN 1176 FMI 3
Turbocharger 1 Compressor Intake Pressure Circuit: circuit voltage high / shorted high - 695 SPN 1174 FMI 4
RBR Turbo Comp Inlet Temp Sens Failed Low: circuit voltage low / shorted low - 694 SPN 1173 FMI 3
RBF Turbo Comp Inlet Temp Sens Failed High: circuit voltage high / shorted high
Look up another code
Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).
Questions
What does Cummins fault code 777 mean?
Cummins fault code 777 is J1939 SPN 1180 FMI 0: Turbocharger #1 Turbine Inlet Temperature High - warning level. In plain terms: turbocharger #1 turbine inlet temperature high: reading above normal (most severe).
Can I keep driving with Cummins code 777?
Usually for a short time, if the engine runs normally and no other warnings are on. Get it diagnosed soon, because many amber codes lead to a derate if ignored. Look at the green, yellow and red examples on this page to judge your situation.
What is the SPN and FMI for Cummins code 777?
SPN 1180 identifies the part or system (Turbocharger #1 Turbine Inlet Temperature High). FMI 0 describes the type of failure: reading above normal (most severe).
What usually causes Cummins code 777?
The most common causes are: boost leak: split charge air hose, loose clamp, cracked charge air cooler; vGT vanes sticking from soot; worn or damaged turbo.
Diesel down in the Midlands?
We work on Cummins-powered pickups, vans and medium-duty trucks across Lexington, Columbia and the Midlands, on site at your yard or roadside.