P0117 — Engine Coolant Temperature Sensor Circuit Low
What it means: Engine Coolant Temperature Sensor Circuit Low.
How serious / can you keep driving: Caution. Limp to the next safe stop.
Check first: Check sensor signal wire for ground fault
Don't risk it — look up listed providers near you and give them this code when you call.
Listed providers nearest Houston, TX
Closest first. Tell them P0117 and what the truck is doing. RoadService.app lists these providers and does not employ them or carry out the repair.
- 0.0 mi away — based in Houston, TX · (832) 377-0578
- 0.0 mi away — based in Houston, TX · (713) 219-9090
- 0.0 mi away — based in Houston, TX · (713) 671-9751
Seen on: Heavy Truck
What P0117 means
Engine Coolant Temperature Sensor Circuit Low. Common causes: ECT sensor shorted to ground.
How serious is it?
Caution. Limp to the next safe stop.
Most likely causes
- ECT sensor shorted to ground
- Wiring damage
- failed sensor
First moves (roadside)
- Check sensor signal wire for ground fault
- replace sensor
FAQ
Engine Coolant Temperature Sensor Circuit Low. Common causes: ECT sensor shorted to ground.
Caution — Limp to the next safe stop.
The most common cause is: ECT sensor shorted to ground. Other possibilities include Wiring damage; failed sensor.
Limp to the next safe stop. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside P0117, or share the same subsystem.
- Coolant level — low (SPN 111 FMI 1)
- Engine Coolant Temperature — Too High (SPN 110 FMI 0)
- Coolant temp sensor — voltage high (SPN 110 FMI 3)
- Coolant temp sensor — voltage low (SPN 110 FMI 4)
- Coolant temperature — moderately high (SPN 110 FMI 16)
- Engine Coolant Over-Temperature Condition (P0217)
- Coolant Thermostat Below Regulating Temperature (P0128)
- Fan 1 Control Circuit Malfunction (P0480)
Same symptom: Running hot
Other codes that show up as coolant temperature climbing or a hot-engine lamp.
- Engine Coolant Temperature Sensor 1 Circuit (P0115) · Cooling
- Engine Coolant Temperature Sensor Range (P0116) · Cooling
- Engine Coolant Temperature Sensor Circuit High (P0118) · Cooling
- Engine Coolant Temperature Sensor Intermittent (P0119) · Cooling
- Fan drive — voltage high (SPN 647 FMI 3) · Engine
- Fan drive voltage low (SPN 647 FMI 4) · Engine
Find a mechanic or related guides
General diagnostic guidance for diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.