P0560 — System Voltage Malfunction
What it means: System Voltage Malfunction.
How serious / can you keep driving: Serious. Power derate likely — plan to stop soon.
Check first: Test battery load
Don't risk it — look up listed providers near you and give them this code when you call.
Listed providers nearest Phoenix, AZ
Closest first. Tell them P0560 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 Phoenix, AZ · (623) 304-4187
- 0.0 mi away — based in Phoenix, AZ · (480) 458-7715
- 0.0 mi away — based in Phoenix, AZ · (480) 530-7347
Seen on: Heavy Truck
What P0560 means
System Voltage Malfunction. Common causes: Unstable system voltage.
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- Unstable system voltage
- Weak battery
- charging system fault
- high resistance ground
First moves (roadside)
- Test battery load
- check alternator output voltage
- inspect main grounds
FAQ
System Voltage Malfunction. Common causes: Unstable system voltage.
Serious — Power derate likely — plan to stop soon.
The most common cause is: Unstable system voltage. Other possibilities include Weak battery; charging system fault; high resistance ground.
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 P0560, 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: Charging and voltage
Other codes that trace back to voltage — one bad ground can set half a dozen of them at once.
- System Voltage Low (P0562) · Electrical, Charging & Network
- System Voltage High (P0563) · Electrical, Charging & Network
- Starter Relay Circuit High (P0619) · Electrical, Charging & Network
- Generator Control Circuit (P0620) · Electrical, Charging & Network
- Generator Field F Terminal Circuit (P0622) · Electrical, Charging & Network
- Generator Field Terminal Circuit Low (P0625) · Electrical, Charging & Network
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.