There are different versions of U3 block coils. Depending on the technology used they differ in primary connections:
- Low voltage connector with two pins: Battery voltage, ignition signal
- Low voltage connector with three pins: Ground, battery voltage, ignition signal
- Low voltage connector with four pins: Ground, Battery voltage, 2x ignition signal (version with two single coils)
U3 Category Block coils have two high voltage connections. The ignition wires connect directly to the spark plugs.
Depending on car and engine type, either multiple coils of the same type are used, or multiple coils of different types are used.
Single spark technology
Four Cylinder - two similar coils U3001:
Fiat Panda(Type 169)
Six Cylinders - three different coils U3005, U3012, U3014:
Renault Espace III
Twin Spark technology
"Twin spark" engines use two spark plugs for each cylinder.
If U3 ignition coils are used, one coil per cylinder (two spark plugs) is required.
Six cylinders, six coils U 3004 + cable set RC-MB223 (12 leads)*:
Mercedes-Benz E320, Engine Code M 112.941