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Electrics and electronics

Problems with the 12 V battery: symptoms, cost and affected models

We have documented 89 faults with the 12 V battery in 4 engines and 84 cars, affecting 98 models of car in our database. The most important by severity and frequency: faulty ICCU: 12 V battery drain and loss of drive power (Hyundai Ioniq 5), battery drain and loose positive cable (BMW Serie 6 E63/E64) and acid leak from the 12 V battery (campaign 18P11) (Ford Galaxy III). At an independent garage, the repair costs from €120 to €500 depending on the engine or car.[1][2]

Documented faults
89
7 of high or critical severity
Engines
4
with at least one fault on this part
Affected models
98
car generations in our database
Garage repair
€120–€500
Depending on engine and car, including VAT

3 sourcesHow we work

How it works and why it fails

12 V battery

The 12 V battery starts the engine and powers the electronics when the car is off. Modern cars have many modules that stay awake for a while after locking, and a module that does not go to sleep (infotainment, alarm, telematics) can drain it in a few days. On hybrids and EVs, a weak 12 V battery prevents starting even if the high-voltage battery is charged.

What to do

If the car will not start after several days parked, test the battery and ask for a parasitic drain test. Batteries in cars with Start&Stop are specific (EFB or AGM): always fit the correct type and register it in the control unit if the manufacturer requires it.

General explanation by MotorFiable. The specific faults of each engine and car, with their sources, are on the linked pages.

Common symptoms

The symptoms that come up most often in the documented faults with the 12 V battery. Open each one to see what other faults cause it.

Problems with the 12 V battery by engine

From most to least important (severity × frequency). Each page details the affected versions and years, symptoms, cost and how to check for it.

  1. 1Medium severityFrequency: Common2.0 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.
  2. 2Medium severityFrequency: OccasionalE-Tech Híbrido12 V battery going flat or needing early replacementSeveral Clio, Arkana and Austral owners with the E-Tech engine document premature replacement of the 12 V auxiliary battery, in one case twice in the first year. It is not the most widespread fault of the system, but it appears repeatedly across different models.
  3. 3Medium severityFrequency: Occasional1.5 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.
  4. 4Low severityFrequency: OccasionalHonda e:HEV / i-MMD12 V battery going flat and hybrid system failing to startIf the car stands unused for a long time, the 12 V auxiliary battery can go flat and the hybrid system does not activate ("Ready" does not appear) even though the traction battery is charged. It is fixed by charging or replacing the battery.Repair (garage): €120–€250

Engines with faults with the 12 V battery

Problems with the 12 V battery by car

Faults documented on specific cars, which occur with any engine. From most to least important.

  1. 1High severityFrequency: CommonHyundai Ioniq 5Faulty ICCU: 12 V battery drain and loss of drive powerThe Integrated Charging Control Unit (ICCU) can fail on the Ioniq 5: it drains the 12 V battery, may refuse to charge and, in the most serious cases, cause the car to lose power or not go into drive mode. Hyundai has replaced this part and updated its software on units built between January and February 2023.
  2. 2High 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.
  3. 3High 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.
  4. 4High severityFrequency: OccasionalFord Mustang Mach-EElectronic door latches that lock when the 12 V battery is flatYes: in 2025 Ford recalled the Mustang Mach-E (2021 to 2025) because, if the 12 V battery drains unexpectedly, the electronic door latches on the front doors keep their last state and can leave someone locked out or locked in. More than 316,000 units are affected worldwide and it is fixed with software.
  5. 5High severityFrequency: OccasionalHyundai Ioniq 6ICCU unit fault and 12 V battery drainAccording to the fiches-auto.fr listing, some owners have an Ioniq 6 immobilised by faults in the ICCU unit or the 12 V auxiliary battery even though the traction battery is charged. The same listing records a 2024 campaign on the 12 V battery charger.
  6. 6Medium severityFrequency: CommonHyundai Kona I12 V battery discharges by itself and leaves the car unable to startIt is the most cited fault of the Kona outside the engine: a compilation of owner testimonies places the 12 V battery as the most repeated category, with spontaneous discharges that leave the car unusable until it is recharged, especially on short journeys.
  7. 7Medium severityFrequency: CommonToyota C-HR IThe 12 V battery goes flat if the car sits unused for several daysThis is the non-engine problem most often cited by C-HR owners: the 12 V auxiliary battery goes flat after several days without using the car, with the monitoring electronics (keyless entry, telematics, multimedia) identified as the cause.Repair (garage): €400–€500
  8. 8Critical severityFrequency: RareFiat 500Risk of the auxiliary battery overheating on mild-hybrid versions (October 2022 campaign)In October 2022 Fiat opened a safety campaign for the mild-hybrid versions of the 500 over a hybrid system deficiency with a risk of the auxiliary battery overheating. The source consulted does not detail the production period or the number of units affected.
  9. 9Medium severityFrequency: OccasionalAlfa Romeo Stelvio12 V battery that goes flat or is replaced several timesIt is a repeated complaint in Stelvio owner testimonies: the 12 V battery fails in winter or does not hold its charge if the car is used little, and some owners have replaced it two or even three times. A Spanish car-leasing portal puts it at between 18 and 24 months of use on well-equipped versions.
  10. 10Medium severityFrequency: OccasionalAlfa Romeo Tonale12 V battery drained by standby drain (Tonale)It is one of the most cited complaints in Tonale owner testimonials: 6 of the 29 collected by fiches-auto mention the 12 V battery, with one case of 15 interventions in two years. The cause that source points to is usually a parasitic drain from modules that don't go to sleep, rather than the battery itself.
  11. 11Medium severityFrequency: OccasionalBMW Serie 5 E39Alternator failure and battery drain on the BMW 5 Series E39According to the owner reports collected by fiches-auto.fr (317 for the 1995-2003 5 Series), there are 13 cases of alternator failure, 7 of battery failure (one that went flat in two days) and 7 of starter motor failure.
  12. 12Medium severityFrequency: OccasionalChrysler 300C12 V battery failures from the third year of useAccording to the ADAC, as cited by German Wikipedia, the 300C breaks down at the roadside relatively rarely, but from the third year of use defective batteries become more common. Some owners link them on forums with minor electronic problems.
  13. 13Medium severityFrequency: OccasionalCitroën C3 IV12 V battery drain and related electrical faultsAccording to the owner reports collected by fiches-auto.fr, some owners suffer rapid 12 V battery drain and voltage drops that cause control unit faults; in one case it was fixed by disconnecting and reconnecting the positive terminal.
  14. 14Medium severityFrequency: OccasionalCitroën C4 IFlat battery as a cause of breakdown assistance call-outsCarWiki cites a flat battery as the main cause of breakdowns on the first-generation C4 between 2006 and 2009, along with some cases of a faulty starter motor in 2006.
  15. 15Medium severityFrequency: OccasionalDacia JoggerAlternator and 12V battery failureCases of a failed alternator at around 30,000 km and of 12V battery problems have been described on the Jogger, although they are a minority among the owner accounts consulted.
  16. 16Medium severityFrequency: OccasionalFiat 500e12 V battery drain and AC charging failuresSeveral owners describe the 500e's 12 V battery draining quickly, especially when the car is "woken up" after a period parked, and AC charging failing at some public points, often because of a connector that is not fully seated.
  17. 17Medium severityFrequency: OccasionalFiat Punto IIBattery draining quickly when the car is parkedAccording to the fiches-auto.fr testimonials (14 cases), the Punto II's battery goes flat within a few days if the car is not used, and there are cases of alternator failure (9) and starter motor failure (7).
  18. 18Medium severityFrequency: OccasionalFord EcoSportBattery drain from parasitic draw and window regulator or central locking faultsfiches-auto.fr documents 12 V battery drain caused by the draw of modules such as the Sync system, as well as isolated faults in the electric windows and central locking of the EcoSport, among the 47 owner testimonies it analyses.
  19. 19Medium severityFrequency: OccasionalFord Ka+12 V battery charge management system fault (campaign 19S21)According to the fiches-auto.fr fiche, campaign 19S21 (August 2019) covers Ka+ models built between September 2017 and May 2019 because the battery charge monitoring system (BMS) may malfunction.
  20. 20Medium severityFrequency: OccasionalFord Kuga IIIThe 12 V battery goes flat because of a parasitic drainThe Kuga III's 12 V battery can go flat with the car parked because of a parasitic drain from the telemetry modules, the Sync system, the body control unit or the hybrid module, which on some units do not shut down completely.
  21. 21Medium severityFrequency: OccasionalHyundai Bayon12 V battery that fails early and can prevent the 48 V system from startingOn the Bayon with the 1.0 T-GDI 48V engine, several owners describe a 12 V battery that goes flat early (one case at 15,000 km) and a starter-generator in the mild-hybrid system that can prevent starting when the voltage is insufficient.
  22. 22Medium severityFrequency: OccasionalHyundai Ioniq12 V battery faults and premature dischargeIn several owner accounts, the Ioniq's 12 V auxiliary battery (on any version) can discharge or fail earlier than expected, leaving the car immobilised or unable to start until it is replaced or recharged.
  23. 23Medium severityFrequency: OccasionalHyundai ix35Battery drain from the interior light or door switchesOn the older units (up to roughly 2012), the battery and the door contact switches can fail and leave the interior light permanently on, which ends up draining the battery if the car sits for a while.
  24. 24Medium severityFrequency: OccasionalHyundai Tucson IV12 V battery drain on the hybrid and plug-in versionsA German buying guide reports occasional cases of 12 V battery drain on 2020-2022 hybrid Tucsons, and a collection of testimonies adds several more mentions among 79 owners, with an electronic module that stays active when the car is parked and can prevent starting after two weeks without use.
  25. 25Medium severityFrequency: OccasionalLand Rover Discovery 5Poor earth contact of the 12 V battery with the chassis: assorted electrical faultsYes: two UK campaigns (R/2020/324 and R/2021/229) corrected insufficient contact between the battery earth stud and the chassis on Discoverys built between September 2018 and March 2021, which could suffer electrical faults of all kinds; Carbuyer adds that the lights could go out unexpectedly.
  26. 26Medium severityFrequency: OccasionalLand Rover Range Rover Sport II12 V auxiliary battery failure on the P400e plug-in hybridAccording to fiches-auto.fr, 4 of the 21 Sport II reports cite failures of the P400e's 12 V auxiliary battery, which is needed for the hybrid to operate; with low voltage, the brake servo and safety systems are disrupted.
  27. 27Medium severityFrequency: OccasionalMazda 3 IVThe m-hybrid system can drain or damage the 12 V batteryOn versions with the m-hybrid mild-hybrid system, some owners describe a sudden drain of the 12 V battery with very low mileage and a progressive loss of charge that forces them to replace it sooner than expected; there is no manufacturer campaign acknowledging the problem as systemic.
  28. 28Medium severityFrequency: OccasionalMercedes-Benz Clase A W168Failures of the 12 V battery, alternator and starter motorIn 2007 ADAC cited battery problems across all registration years of the A-Class W168 and faulty starter motors on petrol models up to 2003. On fiches-auto, the alternator gets 10 mentions among 114 testimonials, the battery 5 and the starter motor 4.
  29. 29Medium severityFrequency: OccasionalMercedes-Benz Clase E W211SAM module faults, false airbag warnings and battery drain on 2002-2003 carsThe first E-Class W211s (2002-2003) account for more electronics complaints: the SAM module can fail and cause lights or wipers to stop working, the front passenger seat occupancy mat triggers airbag warnings for no reason, and in 2005 Mercedes-Benz issued a software update for the on-board power supply manager because of battery drain.
  30. 30Medium severityFrequency: OccasionalMitsubishi ASX IControl unit software that misjudges the 12 V battery's deteriorationUnsuitable engine control unit software could misjudge the deterioration and state of charge of the battery in ASX cars built between June 2010 and September 2011; according to gebrauchtwagenberater.de, this could make the car suddenly stop. The DVSA records a recall that reprograms the software.
  31. 31Medium severityFrequency: OccasionalNissan Leaf IIAbnormal discharge of the 12 V batteryThe Leaf II's 12 V auxiliary battery can discharge abnormally and cause starting failures or multiple error messages on the instrument cluster, a common pattern in electric cars with many systems on standby.
  32. 32Medium severityFrequency: OccasionalRenault Arkana12 V battery drain while the car is parkedSeveral Arkana owners report the 12 V battery going flat after just a few weeks, or even a single battery being replaced twice in a year; Renault has not publicly acknowledged excessive drain at rest, so we treat this as reported by owners and not as a confirmed fault.
  33. 33Medium severityFrequency: OccasionalRenault Austral12 V battery drain while parkedSeveral Austral owners report that the 12 V battery drains while the car is parked, sometimes accompanied by warnings that driver assistance systems or the parking brake are unavailable; Renault has not publicly acknowledged excessive standby drain, so we treat it as reported by owners and not as a confirmed fault.
  34. 34Medium severityFrequency: OccasionalRenault Captur II12 V battery drain while the car is parkedSeveral Captur II owners report the 12 V battery going flat after a few days parked, without Renault having publicly acknowledged excessive drain at rest; there is no press study confirming it as a pattern, so we treat it as reported by owners.
  35. 35Medium severityFrequency: OccasionalŠkoda Enyaq12 V battery failures that can immobilise the carIn a small number of testimonies, the Enyaq's 12 V auxiliary battery (or its DC/DC converter) fails or goes flat and leaves the car unable to start; in one case even the SOS button batteries ran out at 71,500 km. It is not the most cited fault, but it is the one that most often leaves the car stranded.
  36. 36Medium severityFrequency: OccasionalSmart Forfour12 V battery: a common reason for roadside assistance on 2015 to 2017 ForfoursThe German ADAC's breakdown statistics, reproduced by car-recalls.eu, point to the battery as a typical weak point of 2015 to 2017 Forfours, the first years of the W453 generation. The source gives neither the cause nor the cost.
  37. 37Medium severityFrequency: OccasionalSmart Fortwo12 V battery: a common reason for roadside assistance on 2015 to 2017 FortwosThe German ADAC's breakdown statistics, reproduced by car-recalls.eu, point to the battery as a typical weak point of 2015 to 2017 Fortwos, the first years of the C453 generation. The source gives neither the cause nor the cost.
  38. 38Medium severityFrequency: OccasionalToyota Auris IIThe 12 V battery goes flat while the car is parkedSeveral owners describe the 12 V auxiliary battery going flat after the car has been parked for several days, especially on the hybrid versions; cases of alternator faults on the diesel versions are also cited.
  39. 39Medium severityFrequency: OccasionalToyota Corolla XIIThe 12 V battery goes flat if the car sits unused for several daysSeveral owners describe the 12 V auxiliary battery going flat after several days without using the car, especially on hybrid versions; the cause given is the monitoring electronics (keyless entry, telemetry, infotainment) failing to go to sleep.
  40. 40Medium severityFrequency: OccasionalToyota Yaris CrossToyota Yaris Cross 12 V battery drain or failureAccording to the reports gathered by fiches-auto.fr, some Toyota Yaris Cross owners suffer a drained or failed 12 V auxiliary battery, sometimes on an almost new car. It is not a manufacturer campaign.
  41. 41Medium severityFrequency: OccasionalToyota Yaris IVDischarged or failing 12 V battery on the Toyota Yaris IVAccording to testimonies collected by fiches-auto.fr, some Toyota Yaris IV owners suffer a discharged or failed 12 V auxiliary battery, sometimes with an almost new car. It is not a manufacturer campaign.
  42. 42Medium severityFrequency: OccasionalVolkswagen Golf VIII12 V batteries that go flat for no apparent reason and starting failuresA German driving school with 15 Golf 8s told the specialist press that several new 12 V batteries went flat for no apparent reason, leaving up to four cars unable to start in a single month. There is no record of an official manufacturer campaign for this problem.
  43. 43Medium severityFrequency: OccasionalVolvo V40 IIAlternator and 12 V battery failure on the Volvo V40According to the reports on fiches-auto.fr, there are battery and alternator faults, the latter cited at around 80,000-90,000 km. There is no known recall or official data.Appears at around 80,000 km
  44. 44Medium severityFrequency: OccasionalVolvo XC60 IIWeak auxiliary battery (12V/48V) on mild-hybrid versions, with a risk of being left strandedOn mild-hybrid (48V) versions of the XC60 II, several owners describe an auxiliary battery that loses charge more easily than normal, which can leave the car unable to start. fiches-auto.fr documents the pattern, linked mainly to urban use with short journeys.
  45. 45High severityFrequency: RarePeugeot 207Overheating heated seats and battery drain (2007-2009 production)Yes: a 2016 campaign (ref. r2016118) covers cars built between May 2007 and March 2009 on which the battery can drain and the heated seats can overheat.
  46. 46Low severityFrequency: CommonToyota Prius IIIShort-lived 12 V auxiliary battery on the Prius IIIAccording to the fiches-auto.fr page, the Prius III's 12 V battery lasts between two and three years and replacing it costs around 200-250 euros; it is the auxiliary battery, not the traction battery.
  47. 47Medium severityFrequency: RareBMW Serie 2 Gran Tourer F46Rapid drain of the 12 V battery when the car is parkedAccording to the fiches-auto.fr page, some 2 Series Active/Gran Tourer owners suffer rapid 12 V battery drain after parking, attributed to parasitic drain from the multimedia modules, emergency call system or electric tailgate.
  48. 48Medium severityFrequency: RareDacia Duster IIIFlat 12 V auxiliary battery immobilising the Duster IIIThe fiches-auto.fr entry records cases of Duster IIIs that will not start because of a flat 12 V auxiliary battery, one at around 12,000 km, with the electronic parking lock engaged.
  49. 49Medium severityFrequency: RareFiat Panda III12 V battery discharge and Start&Stop system faultsTestimonies from Fiat Panda III owners describe premature 12 V battery discharge and a Start&Stop system that in several cases stops activating; there is no official campaign or specialist press to confirm it.
  50. 50Medium severityFrequency: RareHonda HR-V III12 V battery going flat and repeated battery failuresTwo of the nine HR-V e:HEV testimonials on fiches-auto.fr mention the 12 V battery: one went flat because of the electric tailgate, and another failed several times, with two failed starts in the first ten days. It is a very small sample, not a statistic.
  51. 51Medium severityFrequency: RareIveco Daily VIBattery drain and electrical faults caused by the body control module (BCM)A parts dealer reports that a faulty body control module (BCM) can keep circuits active and drain the battery of 2014 to 2019 Dailies, with interior lights, locks and warning lights failing at random. It is fixed by resetting or replacing the module.
  52. 52Medium severityFrequency: RareKia EV6Premature discharge of the 12 V batteryThree reports in the fiches-auto.fr entry describe a 12 V battery that discharges sooner than expected, with one case at 4 years and effects on door locks and contactors.
  53. 53Medium severityFrequency: RareKia Niro IIAC charging faults and 12 V battery problems in the electric NiroIn the fully electric version of the second generation there are isolated testimonies of a 12 V battery that goes flat, AC charging that stops or is very limited, and a charging flap that is hard to open in damp or freezing weather.
  54. 54Medium severityFrequency: RareMercedes-Benz CLA C118Premature replacement of the 12 V batteryAccording to the fiches-auto.fr data sheet, some CLA C118 owners have had to replace the 12 V battery sooner than expected. It is a case cited in the reports, with no mileage figures or official campaign.
  55. 55Medium severityFrequency: RareMercedes-Benz GLB X24712 V battery: key, starting and control unit faultsAccording to the fiches-auto.fr page, the GLB's 12 V battery causes key, starting and control unit faults; two GLB 200 d owner reports (one at 123,000 km, with an MRM box) document it. It is a pattern of owner reports with no associated campaign.
  56. 56Medium severityFrequency: RareMG MG4Abnormal 12 V battery drainSeveral owners describe the MG4's 12 V auxiliary battery draining abnormally while the car is parked, which can leave it unable to open the doors or start its on-board systems, according to a French compilation of testimonies.
  57. 57Medium severityFrequency: RareMG ZS IAC charging faults and 12 V battery faults on the ZS EVOn the electric version there are isolated reports of a 12 V battery that drains quickly and leaves the car unable to start, and of an on-board charger that refuses AC charging or interrupts it with a warning on the dashboard.
  58. 58Medium severityFrequency: RareŠkoda Octavia IV12 V battery draining for no apparent reasonAn Octavia IV owner describes on a review forum that the 12 V battery does not hold its charge and often ends up flat. There is no official Octavia IV campaign on record for this problem, although the same type of fault has been documented on the Golf 8, with which it shares a platform.
  59. 59Medium severityFrequency: RareToyota bZ4XDischarge of the 12 V auxiliary batteryAccording to the fiches-auto.fr profile, one owner reports repeated discharges of the 12 V battery that prevent starting and trigger several warnings even though the traction battery is charged.
  60. 60Medium severityFrequency: RareToyota Corolla Cross12 V battery that discharges after a few days parked on the Corolla CrossCarWiki records a case of a 2024 Corolla Cross 2.0 hybrid whose 12 V battery went flat in under a week; it was fixed at 7,300 km. It is not a recall, and there is only one case in that database.Repair (garage): €212
  61. 61Low severityFrequency: OccasionalAlfa Romeo GiuliaPremature discharge of the Alfa Romeo Giulia's 12 V batteryAccording to the reports collected by fiches-auto.fr, 8 of 103 Giulia owners mention battery or electrical supply problems, such as flat batteries or batteries that have to be replaced.
  62. 62Low severityFrequency: OccasionalAudi A7 C7Flat battery preventing starting in winterAccording to an ADAC analysis cited by two German guides, the battery is the most frequent cause of breakdown on the A7 C7, especially in winter.
  63. 63Low severityFrequency: OccasionalHonda Civic IXWeak or prematurely failing 12 V battery on the Honda Civic IXThe fiches-auto.fr testimonials cite 12 V batteries failing at 2-7 years on the Honda Civic IX. It is not a documented design fault, but common wear.
  64. 64Low severityFrequency: OccasionalHonda CR-V IV12 V battery drain and alternator fatigueAccording to the reports on fiches-auto.fr, 8 of 142 CR-V IV owners replaced the 12 V battery earlier than expected (a stop/start battery at 64,000 km for €175) and 3 had alternator problems.
  65. 65Low severityFrequency: OccasionalHonda HR-V II12V battery that goes flat or lasts less than expectedOwner testimonies place the 12V battery among the components with the most complaints on the second-generation HR-V, with flat batteries and replacements more frequent than expected.
  66. 66Low severityFrequency: OccasionalHonda Jazz IIWeak 12 V battery or premature failure on the Honda Jazz IIThe fiches-auto.fr reports cite 12 V batteries failing after 2-7 years on the Honda Jazz II. It is not a documented design fault, but frequent wear.
  67. 67Low severityFrequency: OccasionalHonda Jazz IIIWeak or prematurely failing 12 V battery on the Honda Jazz IIITestimonials on fiches-auto.fr cite 12 V batteries failing after 2-7 years on the Honda Jazz III. One case was replaced under warranty at less than 2 years. It is not a documented design fault, but common wear.
  68. 68Low severityFrequency: OccasionalKia Ceed IIDischarged 12 V batteryThe TÜV report in Auto Bild lists discharged batteries as an occasional defect on second-generation Ceeds.
  69. 69Low severityFrequency: OccasionalMercedes-Benz CLA C117Flat or faulty 12 V battery with multiple warnings in the instrument clusterAccording to fiches-auto.fr, 5 of 103 CLA reports cite the battery, and the page notes that a weak auxiliary battery can trigger numerous error messages at once.
  70. 70Low severityFrequency: OccasionalMercedes-Benz Clase E W212Backup auxiliary battery failuresGebrauchtwagenberater and CarWiki report problems with the W212's backup battery: several owners have had to replace it.
  71. 71Low severityFrequency: OccasionalNissan Pulsar12 V battery faulty or flat prematurelyThe fiches-auto.fr file records 12 battery cases among 63 Pulsar owner reports, some with the battery failing within the first year.
  72. 72Low severityFrequency: OccasionalPorsche Cayenne IWeak 12V battery under the driver's seat causing electronic faultsOn the Cayenne I a weak starter battery causes numerous electronic faults. It sits under the driver's seat, which is awkward to reach, so its replacement is often put off. fiches-auto records 5 mentions of the battery out of about 86 testimonies.
  73. 73Low severityFrequency: OccasionalRenault Talisman12 V battery that drains and makes starting difficultGebrauchtwagenberater.de cites 12 V batteries that drain quickly and starting problems as not unusual on the Talisman, and points to the battery as a fault point the ADAC detects on the model.
  74. 74Low severityFrequency: OccasionalSeat Alhambra IIStarter battery failures on the Alhambra, according to ADAC breakdown statisticsADAC breakdown statistics point to the starter battery as the weak spot of the Alhambra II in the 2013-2019 production years, with no other standout weak points.
  75. 75Low severityFrequency: OccasionalSuzuki Swift IVPremature 12 V battery failureAccording to the owner reports on fiches-auto.fr, 12 owners (11 with the 1.2 VVT) replaced the battery, with cases at 55,000 and 70,000 km and a typical life of 4-5 years. There is no official campaign.
  76. 76Low severityFrequency: OccasionalVolkswagen Passat B7Battery drain from an abnormal electrical load, often from the infotainment systemAccording to Auto Express, some Passat B7 cars suffer battery drain from an electrical load that should not occur when the car is parked, often linked to the infotainment system (radio); a testimonial collected by fiches-auto.fr points the same way, with electrical warnings for no apparent reason.
  77. 77Low severityFrequency: RareFord Galaxy III12 V battery draining quickly while the car is parkedTwo owner reports on the fiches-auto.fr page describe a Galaxy 2.0 TDCi 150 hp whose battery goes flat within a few days while the car is parked, one of them with a battery replacement after two and a half years.
  78. 78Low severityFrequency: RareHonda Jazz IVPremature replacement of the 12 V batteryA used-car buying guide for the Jazz IV records some premature replacements of the 12 V battery before 20,000 km and describes them as rare cases. We have found no recalls, bulletins or figures that confirm this.
  79. 79Low severityFrequency: RareInfiniti Q3012 V battery that goes flat within a few weeksThe fiches-auto.fr fiche records 2 cases of a faulty 12 V battery on the Q30, with repeated discharges within a few weeks.
  80. 80Low severityFrequency: RareJaguar E-Pace12 V battery draining quickly while the car is parkedAccording to testimonials on fiches-auto.fr, some Jaguar E-Pace owners report the 12 V battery going flat after about 10-15 days parked, with the car unable to start.
  81. 81Low severityFrequency: RareNissan Micra IV12 V battery that runs down early, especially with Stop & StartThree reports on fiches-auto.fr describe an undersized battery on the Micra IV, especially with the Stop & Start system; the number is very small.
  82. 82Low severityFrequency: RareRenault Clio IVFlat battery and positive terminal touching the alternatorADAC data gathered by car-recalls.eu cites the battery as a common fault on Clios from 2012-2016, and the same page lists a recall for a positive terminal that could touch the alternator heatsink (2012-2019).
  83. 83Low severityFrequency: RareVolkswagen Golf VRCD300 radio that keeps drawing power with the car switched off and drains the batterySome Golf Vs with the RCD300 radio (up to December 2006) could keep drawing current while parked and drain the battery; Volkswagen contacted owners.
  84. 84Low severityFrequency: RareVolvo V60 IIWeak 12 V auxiliary battery that destabilises the electronics and Start-StopAccording to the reports collected by fiches-auto.fr, the 12 V auxiliary battery can cause Start-Stop faults and false warnings from the V60's monitoring system; in one specific case, a D4 190 hp had a fault after the battery was replaced and it was resolved under warranty.
  85. 85Low severityFrequency: RareVolvo V90Auxiliary Start-Stop battery worn out after six yearsA 2017 V90 D4 AWD needed its Start-Stop battery replaced at 150,000 km and around six years, according to the fiches-auto.fr page; the owner considers it normal wear. It is a single report on the page.

Problems with the 12 V battery by make

Problems with the 12 V battery in your car

13 cars have several documented faults with the 12 V battery. Choose yours to see only the ones that affect them, by engine and by year.

Dacia 2
Ford 1
Honda 2
Renault 3
Toyota 5

How much it costs to repair a fault with the 12 V battery

Sorted from the most expensive repair to the cheapest. Prices in Spain including VAT (parts and labour); what each figure includes is on its page.

How we calculate costs · The most expensive repairs across all engines

OBD fault codes with the 12 V battery

The codes the ECU usually stores when this part fails: what they mean, causes and what to check.

Frequently asked questions

Which engines have the most faults with the 12 V battery?

By severity and frequency, the 2.0 and 2.5 Hybrid (the 12 V battery goes flat if the car sits unused for several days, medium severity), the E-Tech Híbrido (12 V battery going flat or needing early replacement, medium severity), the 1.5 Hybrid (12 V battery going flat while parked, medium severity) and the Honda e:HEV / i-MMD (12 V battery going flat and hybrid system failing to start, low severity).

Which cars have problems with the 12 V battery?

Among those we have analysed: Hyundai Ioniq 5 (faulty ICCU: 12 V battery drain and loss of drive power), Ford Galaxy III (acid leak from the 12 V battery (campaign 18P11)), BMW Serie 6 E63/E64 (battery drain and loose positive cable), Ford Mustang Mach-E (electronic door latches that lock when the 12 V battery is flat), Hyundai Ioniq 6 (ICCU unit fault and 12 V battery drain), Hyundai Kona I (12 V battery discharges by itself and leaves the car unable to start), Toyota C-HR I (the 12 V battery goes flat if the car sits unused for several days) and Fiat 500 (risk of the auxiliary battery overheating on mild-hybrid versions (October 2022 campaign)). In total, 84 cars with documented faults with the 12 V battery.

How much does it cost to repair a fault with the 12 V battery?

It depends a lot on the engine or car. At an independent garage, from €120 to €500, including VAT, based on the 3 faults with a documented cost. The most expensive is the 12 V battery goes flat if the car sits unused for several days (Toyota C-HR I).

What symptoms does a fault with the 12 V battery cause?

The most frequently cited in the documented faults: battery goes flat while the car is parked, hard starting or engine will not start, intermittent electronic warnings or sensor faults, electric charging failure or interruption, hybrid system fault warning light or message and gradual loss of power.

Sources

Every fact on this page links to its source. If you find an error, let us know.

  1. Sistema híbrido Honda e:HEV (i-MMD): problemas, fiabilidad y coches que lo llevanMotordex · Technical documentation · consulted 29 October 2026 · in Spanish
  2. Toyota C-HR : fiabilité, pannes et rappelsFiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  3. Toyota Corolla Cross: Probleme, Rückrufe und Erfahrungen der FahrerCarWiki.de · Motoring press · consulted 29 October 2026 · in German