Ford C-Max Alternator: Specs, Fitment & Common Faults
A genuine multimeter test confirms whether it's really the alternator — worth doing before paying for a replacement that might not fix anything.
Illustration for editorial purposes
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OEM Part Number: AG9T-10300-BA (genuine alternator — confirm via VIN) — aftermarket alternators Bosch 0 986 084 230 / Valeo 439906
| Alternators (aftermarket) | Bosch 0 986 084 230 (150 A, freewheel pulley, 6 ribs, 54 mm, reman exchange, plug PL174, excludes vacuum pump, £47.03 surcharge); Bosch 0 986 082 220 (120 A, multi-rib rigid pulley, 6 ribs, 49 mm, reman exchange, plug PL174, excludes vacuum pump, £23.51 surcharge); Valeo 439906 (150 A, freewheel pulley, 6 ribs, 55 mm, new); Valeo 440576 (150 A, freewheel pulley, 6 ribs, 55 mm, reman exchange, £50.24 surcharge); Valeo 440575 (120 A, freewheel pulley, 6 ribs, 55 mm, reman exchange, £48.42 surcharge); Valeo 440688 (150 A, rigid V-ribbed pulley, 6 ribs, 54 mm, reman exchange, £50.24 surcharge); Hella 8EL 015 630-121 (120 A, freewheel pulley, 6 ribs, 54 mm, new); Hella 8EL 015 630-091 (120 A, rigid V-ribbed pulley, 6 ribs, 49 mm, new) |
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| Outputs & variants | 120 A rigid-pulley 49 mm units (Bosch 0 986 082 220, AS-PL A3129, Hella 8EL 015 630-091, Ridex 4G0265) are the 1.6 Ti-VCT petrol fitment; 120 A freewheel units at 54 to 55 mm (Hella 8EL 015 630-121, Valeo 440575, AS-PL A3259) and 150 A freewheel units at 51 to 55 mm (Bosch 0 986 084 230, Valeo 439906 and 440576, Lucas LRA03470, AS-PL A3267S and A3666S) serve the 1.0 EcoBoost, 1.5 and 1.6 EcoBoost petrols and 1.5, 1.6 and 2.0 TDCi diesels, with 150 A the usual diesel and Start-Stop rating; the 150 A units also exist with a 51 mm pulley (AS-PL A3666S, BV PSH 595.911.150.000). |
| Genuine (OE) numbers quoted | TG12C145 (AS-PL A3259, 120 A); FG15T101 (AS-PL A3666S, 150 A); TG12C087 (AS-PL A3129, 120 A); TG15C186 (AS-PL A3267S, 150 A). |
| Fitment notes | Pulley type and diameter decide the fitment at the same amperage, with 49 mm rigid, 51 mm freewheel and 54 to 55 mm freewheel versions all listed, so match the old unit's pulley before ordering. Bosch and Ridex references exclude the vacuum pump. Reman Bosch, Valeo and Lucas units carry surcharges from £23.51 to £50.24; the Hella units are marked for fitting by qualified staff. |
A Genuine Test Worth Doing Before You Replace the Alternator — Ford C-Max Alternator
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.
Ford C-Max Alternator: Often Blamed on the Battery Instead
On the Ford C-Max, 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.
Ford C-Max Alternator: Watch: Replacing It
Mk2 petrol (Grand C-Max only exists from 2010)
Ford C-Max Alternator: What It Does
Running the Ford C-Max'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 C-Max 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.