Ignition Coil 3705010-B04 DX000A0A-3705010-B04 for Changan CS75/CX70/EADO 2011-2018 1.5L

Changan 3705010-B04 is the second generation of the Blue Core pencil coil, and it is the one used on the 1.5 turbo in the CS75, CS75 PHEV, CS55, CX70 and Raeton, and on the 1.5 and 1.6 in the CS35, CS35 Plus and Eado. It looks almost identical to the earlier 3705010-H03 and shares the same DX000A0A supplier code, but the internal suppressor and the boot compound were changed, so the two numbers are listed separately.

The coil is a slim tower with a four pin connector, an integrated igniter and a long ribbed boot. On the 1.5 turbo the plug gap is small and the boost pressure is high, so the coil works at a higher voltage than on the naturally aspirated 1.6, and the secondary insulation is thicker. The mounting eye has a steel sleeve, the body is potted in epoxy, and the connector has a positive latch that must be pressed before the plug will come off, which is the part most often broken by someone in a hurry.

The pattern on these cars is a misfire that starts under acceleration and then becomes permanent, with a flashing engine light and a P030x code. The CS75 1.5T is a heavy SUV and the misfire is often first noticed as a judder when overtaking. Carbon tracking down the inside of the boot, a boot that has gone hard and cracked at the top rib, and oil in the plug well from a leaking cam cover gasket are the three findings that account for most failures. A coil that has been running with a worn plug will often still test within resistance specification but break down under compression, so the swap test is more reliable than a meter.

Remove the engine cover, release the connector latch carefully, undo the bolt and pull the coil straight up. Clean the well, check that the plug is tight and that the gap is correct, and replace the set if the electrodes are worn. Apply dielectric grease to the new boot, press the coil down until it bottoms, torque the bolt to 8 Nm and reconnect until the latch clicks. Clear the codes, run the engine through a heat cycle and road test under load before closing the job.

Supplied as one coil with boot. Four are needed per vehicle. Twelve month warranty.