Number P0563: System Voltage High
The module measures its own supply voltage. CARB allows other monitors to be suspended below 11 V, and above a maker's threshold only if the voltage itself is diagnosed – that is what these codes record. GM's engine modules and Ford's PCM set them without warning lamp. P0563 means the voltage is abo
Can you drive with P0563?
Severity: Plan the repair. Generally yes for normal driving while you arrange the repair, unless symptoms say otherwise.
If you ignore it: Small faults in monitored systems tend to grow; the code will also block an emissions pass in most states.
This is the #111 most common code in our top-150 library, in the electrical, charging & network family (Powertrain system). Severity is Number Nest's editorial triage — if the light is flashing or the car feels unsafe, stop driving it whatever any page says.
What P0563 means
The module measures its own supply voltage. CARB allows other monitors to be suspended below 11 V, and above a maker's threshold only if the voltage itself is diagnosed – that is what these codes record. GM's engine modules and Ford's PCM set them without warning lamp. P0563 means the voltage is above its threshold: GM's engine module 18 V or more in 400 of 500 samples, type C; Saab's 9-4X above 18 V for 5 s. Typical are an overcharging regulator or a jump start or charger at 24 V. Saab's EDC16 diesel reports the same condition as P0560 instead.
Systems involved: battery, alternator, module power supply, engine control module (ECM/PCM).
Causes, ranked by likelihood
| # | Cause | Likelihood |
|---|---|---|
| 1 | Regulator or alternator overcharging | most likely |
| 2 | 24 V jump start or fast charger | possible |
| 3 | Missing battery or poor battery terminal (voltage spikes) | possible |
| 4 | Alternator control line from the module (smart charging) | less common |
Check them in order — the list is ranked so the likely, cheaper causes come before the expensive part.
Symptoms you may notice
- Charge warning
- Bulbs burning out, flickering lights
- Several modules switch off or report faults
Misdiagnosis traps
- Replacing the part named by the code title without testing. The code reports a failed self-test; the cause list above is ranked so the likely, cheap causes are checked before the expensive part is condemned.
- Clearing the code and declaring victory when the light stays off for a day — the monitor that sets this code runs only under specific driving conditions.
(General diagnostic guidance for this code family — no code-specific trap is published for this code.)
How a good shop confirms it
- Confirm the code and record any companion codes — companions narrow the system fast.
- Inspect the affected components and their wiring/connectors for damage, corrosion and looseness.
- Test the top-ranked cause with live data or a multimeter before replacing anything.
(Standard diagnostic path for this family, labeled as general guidance.)
Repair options & costs
| Repair | Shop total (parts + labor) | DIY (parts only) | Difficulty |
|---|
No single repair is costed for this code — the fix follows the diagnosis. The Repair Cost Estimator prices 28 common repairs once you know which one this is.
OBDex repair data for this code rates the job difficulty medium with a typical labor time in the 0.3–2.5 hour range and DIY possible: yes.
Frequently asked questions
How much does it cost to fix P0563?
There is no single fix — the code names a system, and the cost follows whichever cause on the ranked list proves out. The Repair Cost Estimator prices the common repairs in that system; diagnosis (often $100–$180, frequently credited) comes first.
Can I drive with P0563?
See the can-you-drive verdict above — it is based on the system involved and the cascading-damage risk, and it is our editorial triage, not a manufacturer instruction. If the light is flashing or the car feels unsafe, stop driving it regardless of any code.
Will P0563 clear itself?
If the fault was a one-off (a loose cap, a cold-start glitch), the light can go out after several clean trips and the code ages into history. A fault that is still present re-sets the code as soon as the car runs that self-test again — monitors run under specific conditions, which is why "it hasn't come back in two days" is not proof of a fix.
Will my car fail inspection with P0563?
In states with OBD-based emissions inspection, yes — an illuminated check-engine light or an incomplete readiness monitor fails the test regardless of what the tailpipe would show. C-codes (ABS) fall under safety inspection instead in states that have one.
What should I check first for P0563?
The first item on the ranked-causes list above — it is ranked likelihood-first for exactly this reason — plus the free checks: recent work in the area (connectors left loose are a classic), fluid levels, and the battery and grounds on electrical codes.
Where this data comes from
Code facts, causes and symptoms come from OBDex — an open dataset of independently authored descriptions of the standardized generic OBD-II codes (CC0 1.0, public domain; github.com/foerbsnavi/OBDex). The SAE J2012 document itself is copyrighted and is not reproduced here. Cost ranges are Number Nest's own US planning model: national parts and labor ranges cross-checked against the CarMD Vehicle Health Index 2026 published averages, with labor adjustable by the BLS OEWS May 2025 state wage index for auto technicians (occupation 49-3023) — a wage index, not a surveyed shop rate. Severity and can-you-drive notes are our editorial triage, not a manufacturer instruction.