Power Supply Voltage Too Low
The power supply voltage is below the acceptable level for the system to operate properly.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The engine's computer is getting less voltage than it needs. Normally, it needs around 12 volts but is only getting 10 volts or less, which can make it run poorly or not at all.
What the computer is actually seeing
The vehicle's computer monitors its supply voltage constantly. If the voltage drops below a threshold (usually around 10.5 volts), the code SPN 568 will set.
What a healthy reading looks like
Normal operating voltage is between 12.0 to 14.5 volts while the engine is running.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the battery voltage with a multimeter. It should read between 12.0 to 14.5 volts for normal operation. If below 12.0 volts, charge or replace the battery.
- 22. Inspect the battery terminals and connections for corrosion or looseness. Clean and secure as necessary.
- 33. Start the vehicle and check the voltage at the alternator's output terminal. It should also be between 12.5 to 14.5 volts. If not, the alternator may be faulty.
- 44. Verify grounding points from the battery to the engine and chassis. Ensure there are no breaks or excessive corrosion.
- 55. Use a wiring diagram to check for any damaged wiring between the battery, alternator, and ECU. Repair or replace any damaged wires.
Common causes
- Weak or drained battery
- Corroded battery terminals
- Faulty alternator
- Poor grounding
- Damaged wiring harness
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Driving with low voltage can lead to electrical system malfunctions, so it's advisable to address it as soon as possible.
Will this code come back after clearing?
Yes, if the underlying issue (such as a weak battery or bad alternator) isn't fixed, it will likely return.
Why does this sometimes pair with other codes?
Low voltage can affect multiple systems, leading to additional fault codes being triggered.
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