Mazda CX-3 Alternator: Specs, Fitment & Common Faults
On the CX-3, a "Charging System Malfunction" message is often genuinely a software glitch, not a true hardware failure.
Illustration for editorial purposes
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OEM Part Number: P51X-18-300B (genuine alternator — confirm via VIN) — aftermarket alternators Bosch 1 986 A00 631 / Lucas LRA04006
| Alternators (aftermarket) | Bosch 1 986 A00 631 (100 A, rigid multi-rib pulley, 6 ribs, 51 mm, new, plug 139, excludes vacuum pump); Bosch 0 986 084 990 (100 A, rigid multi-rib pulley, 6 ribs, 51 mm, remanufactured exchange, plug 139, core charge £24.86); Lucas LRA04006 (150 A, 6 ribs, 51 mm, remanufactured, plug 0314, core charge £25.12); Lucas LRA03875 (100 A, 6 ribs, 51 mm, remanufactured, plug 0200, core charge £50.24); AS-PL A5436S (150 A, freewheel pulley, 6 ribs, 51 mm, new, plug PL_3310); AS-PL A5543S (150 A, freewheel pulley, 6 ribs, 51 mm, new, plug PL_3407); AS-PL A5616S (100 A, 6 ribs, 51 mm, new, plug PL_3310). |
|---|---|
| Outputs & variants | Confirm the amperage and pulley type against the old unit |
| Genuine (OE) numbers quoted | A5TJA091 (AS-PL A5616S); A2TX4781ZT (AS-PL A5436S); A5TL0491 (AS-PL A5337); A2TX9481 (AS-PL A5543S). |
| Fitment notes | The CX-3 shares its alternators with the Mazda 2 and 3 of the same era, so match by the Mitsubishi A2TX/A5TJ number on the old unit; remanufactured Bosch, Lucas and Autoelectro units carry core charges of £25-£60. |
A Genuinely Important Warning Worth Knowing Before Replacing the Alternator — Mazda CX-3 Alternator
If you're seeing a "Charging System Malfunction" or "Low Battery Risk" warning message, particularly on a relatively new car, this is genuinely worth knowing: this specific warning has been widely reported as often being a software sensitivity issue related to the Body Control Module, rather than a genuine hardware failure. It's worth asking a dealer directly whether a relevant software fix exists before assuming the alternator needs replacing.
It's also worth knowing that alternator fitment is genuinely more complex than it might first appear — the correct part depends on engine size, the specific transmission fitted, and whether the engine has cylinder deactivation.
Mazda CX-3 Alternator: Often Blamed on the Battery Instead
On the Mazda CX-3, dim lights, slow starts, a battery that won't hold charge — these symptoms point equally to a weak battery or a failing alternator, and that overlap is why so many replacements target the wrong part first, with the real problem only surfacing weeks later.
Mazda CX-3 Alternator: Watch: Replacing It
No CX-3 video; Skyactiv-G alternator mounting is common across the range
Mazda CX-3 Alternator: What It Does
Electricity generation while the Mazda CX-3's engine is running is the alternator's job, charging the battery and directly powering the electrical systems. When it's working properly, the battery mostly just handles engine starting and short demand spikes, not day-to-day electrical load.
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Mazda CX-3 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 Mazda Alternator
The same part, covered across other Mazda models.