Electrical system and control unitsGeneric OBD-II codeUrgency: Garage soon
Code P0563: high voltage in the electrical system (overcharging)
P0563 means: system voltage high.[1][2][3] A control module has measured the car's 12 V supply rising above a maximum value and staying there for a time. AutoDTCs puts this above about 16 V for around 5 seconds or more, with a normal voltage of 13 to 15.2 V with the engine running. Saab's workshop documentation for the 9-4X gives, for the whole group of system voltage codes, about 18 V for around 5 seconds with the engine running (and about 9 V as the lower limit). The threshold is set by each manufacturer.[1][2]
What code P0563 means
A control module has measured the car's 12 V supply rising above a maximum value and staying there for a time. AutoDTCs puts this above about 16 V for around 5 seconds or more, with a normal voltage of 13 to 15.2 V with the engine running. Saab's workshop documentation for the 9-4X gives, for the whole group of system voltage codes, about 18 V for around 5 seconds with the engine running (and about 9 V as the lower limit). The threshold is set by each manufacturer.[1][2]
AutoDTCs describes it as a fault on the charging side, not a weak battery, and explains that, as all the modules share the 12 V bus, several may store the code at the same time. Saab's documentation adds a clue: if several modules have high or low voltage codes, or abnormal values, it points to a problem with the charging system.[1][2]
Sustained high voltage can make the battery boil and damage bulbs and electronic modules. A recent jump start, a charger connected to the battery or a heavily discharged battery can leave the code without any real fault, according to AutoDTCs, and Saab's documentation also mentions the charger and jump starting.[1][2]
Original definition (SAE J2012): System Voltage High[1][2][3]
Causes of P0563
From most to least likely, according to the sources.
- 1Faulty voltage regulator, usually built into the alternator, stuck at full excitation. AutoDTCs lists it first.[1]
- 2Overcharging alternator. PartsAvatar warns that the battery is often replaced unnecessarily and that the alternator is the most common cause.[1][3]
- 3Regulator control circuit broken, short-circuited or with high resistance between the control unit and the alternator, or a cable between the battery and the alternator with high resistance.[1][3]
- 4Faulty or badly connected battery current sensor, which gives the control unit a wrong idea of the battery's state. On some cars (AutoDTCs cites Jeeps), the charging logic depends on that reading, so the battery and its earths should be checked first.[1]
- 5Battery connections and earths in poor condition.[1][2]
- 6Occasional external causes: a recent jump start, a charger connected or a heavily discharged battery.[1][2]
- 7Faulty control unit: according to PartsAvatar, only if all the other tests fail.[3]
Symptoms
- Engine or charging warning light on, often with high-voltage codes in several modules.[1][3]Engine warning light: faults that cause it
- Instrument panel voltmeter (where fitted) near or above 16 V with the engine running.[1]
- Headlights and interior lights too bright, and bulbs that blow more often.[1]
- Battery hot, swollen or bubbling, sometimes with a sulphur smell from the boiling electrolyte.[1]
- Flickering screens, modules that reset or accessories that work intermittently.[1]Electronic warnings: faults that cause it
- According to PartsAvatar, hard starting or an engine that stalls after starting, an automatic gearbox that does not shift, and higher consumption.[3]Hard to start: faults that cause it
How to diagnose P0563
In order: from the most likely and cheapest to check to the most expensive.
- 1Read the codes from all the modules, not only the engine, and check whether the code is current or historical. If the car has just had a jump start or a charge, clear the codes and check again before replacing parts.[1][2]
- 2Measure the battery voltage with the engine off: Saab's documentation expects it to settle between 12.4 and 12.8 V. Then, with the engine running and the accessories off, it should be at least 1 V higher and below 15 V. AutoDTCs gives 13 to 15.2 V and PartsAvatar 13.2 to 14.7 V under load, with more than 15.5 V as a sign of a fault in the charging system. Keep the engine below 2,000 rpm: AutoDTCs warns that above that, some alternators self-excite and give a false high reading.[1][2][3]
- 3Test the battery under load and check the terminals, cables, earth straps and the battery current sensor connector: corrosion, play or damage.[1][2]
- 4Test the regulator and its control circuit: measure in the circuit (by probing the connector from behind) that the control unit's command follows demand instead of staying at full excitation, and look for continuity and short circuits to positive between the alternator and the control unit. If the signal is correct but the output voltage stays high, replace the internal regulator or the alternator.[1]
- 5With the diagnostic equipment, check the supply (B+) and ignition voltage each module sees: it should be within 1 V of the battery voltage.[2]
- 6After repair, clear all the modules, measure the voltage at idle and under a light load to confirm it stays in the normal range, and replace bulbs or other parts damaged by the overvoltage.[1]
Can I keep driving with P0563?
Garage soon
AutoDTCs rates it as moderate severity: the car usually keeps running, but sustained overvoltage can make the battery boil and damage bulbs and electronic modules. It advises driving only briefly and repairing it soon to protect the electronics, and not continuing to use the car for days. PartsAvatar gives no severity rating and does not say whether the car can be driven.[1][3]
Parts related to code P0563
The parts that most often cause this code. The code points to the circuit, not always the part: diagnose before you buy.
Alternator
Battery
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Documented faults related to P0563
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Alternator and starter motor: the most serious faults by engine and car
- High severityFrequency: Occasional2.2 JTDm Multijet IIAlternator cable touching the exhaust gas recirculation pipe (fire risk)An Alfa Romeo campaign covers diesel Stelvio built between 18 January 2017 and 18 September 2018: an alternator cable may rub against the exhaust gas recirculation pipe and cause a short circuit, with a fire risk in the worst case.
- Medium severityFrequency: Occasional1.7 CDTIPremature alternator wearThe Hitachi-brand alternator fitted at the factory to the 1.7 CDTI tends to wear out sooner than expected, according to a German buying guide on the Opel Astra H, with typical replacements at around 140,000 km; there are similar accounts on the Opel Meriva with this engine.
- Critical severityFrequency: OccasionalAlfa Romeo JuniorRisk of electric arcing at the 48 V starter-generator terminal on the hybrid JuniorYes: a March 2026 Safety Gate alert (campaign F60F) covers Junior MHEVs built between 27 November 2023 and 18 December 2025. The clearance between the particulate filter pipe and the 48 V starter-generator terminal cover is under 10 mm and, in damp conditions, there could be electric arcing and fire.
- Critical severityFrequency: OccasionalBMW Serie 3 G202025 campaign for corrosion of the starter motor relay (risk of fire)Yes: in September 2025 BMW recalled, among other models, the 2019 to 2021 330i (G20) because the starter motor relay can corrode, overheat and cause a short circuit with a risk of fire even when the car is parked.
12 V battery: the most serious faults by engine and car
- High severityFrequency: CommonHyundai-Kia E-GMP (Ioniq 5, Ioniq 6, EV6)Faulty ICCU: 12 V battery drains, charging fails and power is lostThe ICCU, which combines the on-board charger and the converter that powers the 12 V system, can fail on the Ioniq 5, Ioniq 6 and EV6: it cuts AC charging, drains the 12 V battery and, in the worst case, the car loses power and stops. Hyundai and Kia have recalled units built from 2021 to 2024.Repair: €2,000–€5,000
- Medium severityFrequency: Very frequent1.5 Hybrid12 V battery going flat while parkedYes: on the hybrid Yaris and Yaris Cross, the 12 V battery can go flat within a few days while parked because of the residual draw of modules such as eCall or keyless entry. It is fixed with a software update or, if the battery is already damaged, by replacing it.
- Medium severityFrequency: Very frequent1.8 HybridThe 12V battery drains on the C-HR and Corolla hybridsYes: on the first-generation C-HR hybrid, the 12V battery is one of the most frequently reported faults: it runs flat after a few days standing or on short trips, and the car will not start. The ADAC and Toyota itself point to it as a cause of faults on the C-HR and Corolla.
- Medium severityFrequency: Very frequent2.0 and 2.5 HybridThe 12 V battery goes flat if the car sits unused for several daysYes, it is a common complaint: the 12 V battery can go flat after just a few days without using the car, because of the standby drain from the electronics (multimedia, telematics, keyless entry). With the 12 V battery very low, the hybrid system can lock itself into a safe mode.
- High severityFrequency: OccasionalBMW Serie 6 E63/E64Battery drain and loose positive cableThe battery and alternator are frequently cited by Fiches-auto, and there is a recall for the battery's positive cable, which can work loose.
- High severityFrequency: OccasionalFord Galaxy IIIAcid leak from the 12 V battery (campaign 18P11)According to the fiches-auto.fr page, campaign 18P11 (August 2019) covers Galaxies built between February 2014 and February 2019 over a risk of battery acid leaking, which can worsen over time.
Wiring, connectors and short circuits: the most serious faults by engine and car
- Critical severityFrequency: OccasionalBMW N62 / N63Additional turbo coolant pump with a risk of short circuit and fireIn 2011 BMW recalled 5, 6 and 7 Series, X5 and X6 models built between 2007 and 2011 because of the additional turbo coolant pump: moisture, a short circuit and, in extreme cases, a fire. In 2012 there was another campaign for a crack in the pump, with a more robust version.
- Critical severityFrequency: Occasional1.6 GDi híbrido (Kappa)Main relay of the power relay assembly (overheating and fire risk)Yes, on the first units: Hyundai and Kia recalled 2016–2018 Ioniq and Niro hybrids and plug-in hybrids because the main relay that connects the high-voltage battery could come loose, overheat and, in the worst case, cause a fire.
- Critical severityFrequency: Occasional1.6 GDi híbrido (Kappa)Clutch hydraulic actuator (HCA): leak or moisture with risk of short circuit and fireYes, this is the most documented hybrid system fault: the hydraulic actuator that engages the combustion engine with the hybrid assembly has had two recalls (2018 for a leak on the Niro and 2025 for moisture in its electronic board on the Niro, Ceed and XCeed PHEV), with a risk of short circuit and fire.
- High severityFrequency: Occasional1.3 TCeBlown fuel pump fuseOn the Renault Captur II and Clio V with the 1.3 TCe engine, a 20-amp fuse can blow and leave the car without an engine. According to L'argus, in April 2021 this fault still had no factory fix; the official service centre's diagnosis includes checking, and sometimes replacing, the catalytic converter.
- Critical severityFrequency: CommonRover 75Seat SRS connector fault with airbag and seatbelt warning light onAuto Express warns that the Rover 75's seat SRS connector can cause the airbags to fail, and dealers were fixing it with revised connectors. The Dutch APK inspection puts the airbag or seatbelt fault warning among the most frequent defects across almost all series.
- Critical severityFrequency: OccasionalAlfa Romeo GiuliettaShort circuit from badly routed wiring that can prevent gear shifting (KBA campaign, 2010-2015)Yes: according to Germany's KBA, on Alfa Romeo Giulietta cars built between 2010 and 2015 inadequate cable routing could cause a short circuit and, as a result, gear-shift failure.
Frequently asked questions
Can I drive with code P0563?
Only briefly and with the intention of repairing it soon. AutoDTCs rates it as moderate severity: the car usually keeps running, but sustained overvoltage can boil the battery and damage bulbs and modules, and it does not advise using it like this for days.[1]
What is the difference between P0563 and P0562?
They are opposites. P0562 indicates a system voltage that is too low and P0563 one that is too high. AutoDTCs notes that the latter points to the charging side (alternator, regulator and its control circuit) and not to a weak battery, and Saab's documentation groups them with P0560 in the same voltage diagnostic procedure.[1][2]
Can a jump start cause the code?
Yes. AutoDTCs and Saab's documentation state that a recent jump start, a connected charger or a heavily discharged battery can raise the voltage enough to store the code without a real fault. That is why it is worth clearing it and checking whether it returns before replacing parts.[1][2]
What voltage should the alternator produce?
With the engine running, between 13 and 15.2 V according to AutoDTCs, and between 13.2 and 14.7 V under load according to PartsAvatar. Saab asks for at least 1 V more than the parked battery and less than 15 V. Above about 15.5 V, PartsAvatar suspects the charging system. The exact figure is given by the manufacturer.[1][2][3]
Will I pass the MOT with code P0563?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[4]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- P0563: System Voltage HighAutoDTCs · Technical documentation · consulted 31 October 2026
- DTC B1325, B1330, B1517, C0800, P0560, P0562 or P0563 (9-4X 2011)Saab WIS Online (Saab Workshop Information System) · Technical documentation · consulted 31 October 2026
- P0563 OBD Error Code: System Voltage HighPartsAvatar · Technical documentation · consulted 31 October 2026
- Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish