P0615 — Starter Relay Circuit Fault
What it means: Starter Relay Circuit Fault.
How serious / can you keep driving: Serious. Power derate likely — plan to stop soon.
Check first: Test starter relay coil and contacts
Don't risk it — look up listed providers near you and give them this code when you call.
Listed providers nearest Sparks, NV
Closest first. Tell them P0615 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 Sparks, NV · (775) 355-6884
- 0.0 mi away — based in Sparks, NV · (775) 356-7200
- 0.0 mi away — based in Sparks, NV · (775) 359-0550
Seen on: Heavy Truck
What P0615 means
Starter Relay Circuit Fault. Common causes: Starter relay circuit open or shorted.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- Starter relay circuit open or shorted
- Failed relay
- wiring fault
First moves (roadside)
- Test starter relay coil and contacts
- check relay power supply
FAQ
Starter Relay Circuit Fault. Common causes: Starter relay circuit open or shorted.
Serious — Power derate likely — plan to stop soon.
The most common cause is: Starter relay circuit open or shorted. Other possibilities include Failed relay; wiring fault.
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside P0615, or share the same subsystem.
- ECU Power Supply — Intermittent / Erratic (SPN 627 FMI 2)
- Battery / Charging Voltage — Low (SPN 168 FMI 18)
- Engine Controller (ECM) — Internal Fault (SPN 629 FMI 12)
- Battery voltage low during crank (SPN 168 FMI 17)
- J1939 proprietary datalink lost (SPN 625 FMI 9)
- J1939 Data Link — Communication Error (SPN 639 FMI 2)
- High Speed CAN Bus Fault (U0001)
- Lost Communication with ECM/PCM (U0100)
Same symptom: Won't start or won't crank
Other codes that end in a truck that will not light off, especially cold.
- Starter Relay Circuit Low (P0616) · Electrical, Charging & Network
- Starter Relay Circuit High (P0619) · Electrical, Charging & Network
- Intake air heater voltage high (SPN 729 FMI 3) · Engine
- Crankshaft/Camshaft Correlation Bank 1 Sensor A (P0016) · Engine
- Glow Plug/Heater Circuit A (P0380) · Engine
- Intake Air Heater Circuit Fault (P0540) · 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.