Ford Puma Alternator: Specs, Fitment & Common Faults

A simple multimeter test confirms whether it's genuinely the alternator — and why some replacement units develop the exact same fault.

Illustration for editorial purposes

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OEM Part Number: P1T111238AA (genuine alternator — confirm via VIN) — aftermarket alternators AS-PL A6789S

Accuracy note: Covers the Ford Puma (2019-) as listed in the UK aftermarket catalogues. Alternators are sold by output (amps), pulley type and plug, and the same model usually has two or three units depending on engine, start-stop and the electrical load of the trim — a 120 A unit on a car built for 150 A will undercharge, and a rigid pulley on a car designed for a freewheel clutch pulley will shred belts. The references below are UK aftermarket catalogue listings for this generation, labelled by brand; many are remanufactured exchange units that carry a core charge until the old alternator is returned. Genuine numbers are shown only where a listing quotes one. Check the amp rating, pulley and plug stamped on the old unit, or confirm via VIN, before ordering.

Alternators (aftermarket)	AS-PL A6789S (150 A, freewheel clutch pulley, 6 ribs, 52 mm, new, PL_2305 plug); Rotovis 9091396 (150 A, freewheel clutch pulley, 6 ribs, 52 mm, reman, COM plug with B+ M8); Rotovis 9091407 (150 A, freewheel clutch pulley, 6 ribs, 54 mm, reman, COM plug with B+ M8); Casco CAL10100AS (150 A, freewheel clutch pulley, 6 ribs, 54.3 mm, new, CPA0016 plug, integrated regulator, SEG original fitment only); DRI 2193461502 (150 A, freewheel clutch pulley, 6 ribs, 52 mm, reman exchange, plug 0213 with M8 B+ and COM/LIN2, core charge GBP 50.35); BV PSH 595.973.150.050 (150 A, freewheel clutch pulley, 6 ribs, 52 mm, new, B+ M8); AS-PL A01202(SEG) (210 A, 48 V, rigid belt pulley, 6 ribs, 54 mm, new, PL_5201 plug, mild-hybrid only).
Outputs & variants	The 12 V alternator for the 1.0 EcoBoost and 1.5 EcoBlue is a 150 A unit on a 52 mm (or 54 mm) six-rib freewheel clutch pulley, with 130 A and 180 A variants also appearing. The 1.0 EcoBoost mHEV uses a separate 48 V belt-driven starter-generator at 210 A or 250 A on a rigid six-rib pulley, which is a different part entirely. The 70 A to 105 A units also listed under this model belong to the 1997-2002 Puma coupe and do not fit the 2019-on car.
Genuine (OE) numbers quoted	AS-PL A6789S quotes 104211-9540; AS-PL A01202(SEG) quotes 0127813050; AS-PL A5033 quotes A5TA4391 (old coupe only).
Fitment notes	The mild-hybrid 48 V starter-generator and the 12 V alternator are not interchangeable and the 48 V unit should only be fitted by someone equipped for high-voltage work; renew the freewheel clutch pulley with the alternator; exchange units from DRI, Walker and Autoelectro carry refundable core charges from GBP 50 up to GBP 251 for the 48 V parts; Casco CAL10100AS is listed only as a replacement for the SEG (former Bosch) original unit.

Confirm the Alternator Before You Pay for a Replacement

With the engine running, a multimeter across the battery terminals should read roughly 13.8-14.5V — notably lower readings suggest the alternator isn't charging properly, while readings well above 14.5V point to a failing voltage regulator instead. A whining noise that gets louder when heavy electrical loads switch on is a strong practical indicator worth checking before assuming the worst.

Worth knowing when buying a replacement: Several Ford owners report remanufactured or budget aftermarket alternators developing the same whining noise shortly after fitting. A well-reviewed reconditioned unit or low-mileage genuine used alternator is frequently the safer bet over the cheapest reman option.

Ford Puma Alternator: Often Blamed on the Battery Instead

On the Ford Puma, it's genuinely hard to tell a weak battery from a failing alternator just from symptoms — both produce dim lights, slow starts, and a battery that won't hold charge. That's exactly why so many people end up replacing the wrong part, then returning to the garage a few weeks later.

Before you buy: alternator output rating varies by engine size and trim, particularly on cars with more onboard electronics. Always confirm against your VIN before ordering.

Ford Puma Alternator: Watch: Replacing It

🎬 Watch: Ford Ecoboost owners, here's how to remove your faulty alternator (sister (fiesta/focus 1.0 ecoboost))

Watch on YouTube ↗

No Puma-specific video; same 1.0 EcoBoost engine as Puma, model in video not stated

Ford Puma Alternator: What It Does

Running the Ford Puma's electrical systems and keeping the battery charged while the engine turns over — that's the alternator's role. A properly functioning one means the battery only really needs to worry about starting the car and absorbing occasional spikes in demand.

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Ford Puma Alternator: Warning Signs, DIY Difficulty & Aftermarket Advice

These are the same regardless of make or model — see our full Alternator Guide for symptoms to watch for (plus a genuinely useful two-minute test to confirm it's not the battery instead), confirming the right amperage and fitment against your VIN, and which brands are worth trusting.

More Ford Alternator

The same part, covered across other Ford models.