Xenon bulb D4S – Mercury-free replacement

The D4S is mainly used on Japanese vehicles: Toyota Avensis, Corolla, RAV4, Land Cruiser, Lexus IS, GS, RX, Subaru Outback, Forester, Mazda 3, 6 and CX-5. It is the mercury-free version of the D2S, with a specific separate D4 ballast. Some recent European vehicles also use it. The D4S only works with a D4 ballast, incompatible with D2 ballasts. Consult the AGM Vision sheets to check the exact compatibility.

The D4S and the D2S have a similarly shaped base (P32d-5 for the D4S, P32d-2 for the D2S), but with different keying tabs that physically prevent interchange. The D4S uses a mercury-free gas chemistry and requires a D4 ballast, with a specific ignition voltage and frequency. Forcing a D2S into a D4 socket (or vice versa) can damage the ballast and the bulb. If in doubt, remove the original bulb and check the engraved reference on the base.

The D4S is generally more expensive than the D2S due to its newer mercury-free technology, lower-volume production, and more costly substitute metal salts. The D4S market is also smaller, as it is mainly fitted to Japanese vehicles. However, the price gap is narrowing over time. AGM Vision offers OEM-quality D4S bulbs at competitive prices, with an optimal value for money and a manufacturer’s warranty on each bulb.

No, the D4S and the D4R are not interchangeable. The D4S is designed for projector lens optics, where the lens cuts off the beam. The D4R includes an opaque shield painted on the glass for reflector optics. Installing a D4S in a reflector optic produces a beam without cutoff that dazzles dangerously. Both share the same D4 ballast, but the base has different keying tabs. Check the exact reference before ordering from AGM Vision.

A faulty D4 ballast shows several symptoms: a bulb that does not light up, that flickers, that turns off after a few seconds, or that changes color (pink, purple). To test, swap the two bulbs from side to side: if the problem follows the bulb, the bulb is the cause. If the problem stays on the same side, the ballast is the cause. A multimeter can check that the ballast delivers the correct voltage. AGM Vision offers replacement OEM and aftermarket D4 ballasts, with warranty.

The D4S 55W bulbs are available in an aftermarket version for enhanced lighting. They produce about 40% more lumens compared to the original 35W version. However, the original D4 ballast is calibrated for 35W and cannot power a 55W. A compatible D4 55W aftermarket ballast is required. This modification is not approved and reduces the bulb’s lifespan. It is reserved for off-road and competition. AGM Vision offers both versions.