Seat Leon Battery: Specs, Fitment & Common Faults

A genuine, technical cause of persistent battery drain: incorrect BCM coding can keep the whole CANBUS network awake — plus what a stop-start "unavailable" warning genuinely signals.

Illustration for editorial purposes

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OEM Part Number: Type 096

Accuracy note: The Leon Mk3 (2012–2020) takes a 278 mm type 096 EFB or AGM (70Ah / 760A) on the 1.4 TSI, 1.5 TSI and 2.0 TDI stop-start cars, and a 242 mm type 027 standard (62Ah) on early non-stop-start 1.2 TSI and 1.6 TDI 90s. The Mk4 (2020 on) is 096 EFB throughout; the e-Hybrid has a 12V auxiliary. VW Group cars need the new battery coded. Check the three-digit type code, Ah and CCA printed on the battery you are removing before ordering — this model was built in more than one size. Stop-start cars must have an EFB or AGM battery, never a standard one.

Mk3, 1.2 TSI / 1.6 TDI 90 without stop-start	Type 027 standard (62–63Ah / 550–610A, Varta D15 / Bosch S5 005). Aftermarket: Yuasa YBX3027 (62Ah / 550A); Varta D15 / C22; Bosch S4 005
Mk3, 1.4 TSI 125 / 140 / 150 ACT stop-start	Type 096 EFB or AGM (70Ah / 760A). Aftermarket: Yuasa YBX7096 EFB (75Ah / 700A) or YBX9096 AGM (70Ah / 760A); Varta N70 EFB / A7 AGM; Bosch S4E 081 / S5A 080
Mk3, 1.6 TDI 115 / 2.0 TDI 150 / 184 stop-start	Type 096 AGM (70Ah / 760A). Aftermarket: Yuasa YBX9096 AGM (70Ah / 760A); Varta A7; Bosch S5A 080
Mk3 Cupra 280 / 290 / 300	Type 096 AGM (70Ah / 760A) — code after fitting. Aftermarket: Yuasa YBX9096 AGM (70Ah / 760A); Varta A7; Bosch S5A 080
Mk4 (2020 on), 1.0 / 1.5 TSI, 2.0 TDI, 2.0 TSI	Type 096 EFB (70–75Ah / 700–760A). Aftermarket: Yuasa YBX7096 EFB (75Ah / 700A) or YBX9096 AGM (70Ah / 760A); Varta N70 EFB / A7 AGM; Bosch S4E 081 / S5A 080
Mk4 e-Hybrid	12V auxiliary battery — confirm via VIN

A Genuine, Technical Cause Worth Knowing: Incorrect Factory BCM Coding — Seat Leon Battery

A genuinely specific, well-documented cause of persistent battery drain across the wider Ibiza/Leon platform traces back to the Body Control Module (BCM) being coded incorrectly for the car's actual configuration — for example, coded as if the car has a different door count or equipment level than it genuinely has. When this happens, the module continuously looks for components that don't physically exist, which keeps the CANBUS network in an awake state rather than allowing it to properly sleep when the car is parked, draining the battery even with everything switched off correctly. Confirming the coding matches the car's genuine specification exactly requires careful matching of equipment codes — a specialist familiar with VCDS or the online SEAT parts/coding database can check this properly.

Worth knowing if stop-start keeps showing "unavailable": this can genuinely be an early warning sign of a battery on its way out, even if a basic test suggests it's still fine — one owner reported stop-start becoming intermittently unavailable specifically after the car sat unused for a couple of days, resolving after an overnight charge on a proper smart charger, which is a documented pattern worth recognising rather than ignoring as a minor inconvenience.

Seat Leon Battery: Watch: Replacing It

🎬 Watch: Seat Leon Mk3 (2013–2019) battery removal and replacement

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Filmed on a Mk3 Leon.

Seat Leon Battery: The Part Everyone Blames First, Not Always Correctly

A Seat Leon that won't start gets blamed on the battery more often than any other component, and it's right often enough to make that assumption a reasonable first check. But it's not always the actual cause, which is worth knowing before spending money on a replacement that doesn't fix anything.

Before you buy: battery size, capacity and type (standard vs AGM/EFB for stop-start systems) vary by trim and engine. Always confirm against your VIN before ordering.

Seat Leon Battery: What It Does

The Seat Leon's 12V battery provides the power needed to start the engine and runs electrical systems when the engine isn't turning. On cars with stop-start technology, the battery works much harder than on older designs, since the engine switches off and restarts far more frequently — which is exactly why these cars need a specific AGM or EFB battery type rather than a standard unit.

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Seat Leon Battery: Warning Signs, DIY Difficulty & Aftermarket Advice

These are the same regardless of make or model — see our full Battery Guide for warning signs to watch for, confirming fitment against your VIN, and matching the right technology (standard, EFB, AGM) when buying aftermarket.

More Seat Battery

The same part, covered across other Seat models.