VAG measuring blocks

Every VW-group control unit of the K-line and early CAN era reports its live data the same way: as numbered groups of four values. Ask the engine for group 115 and it answers with engine speed, load, boost specified and boost actual. VCDS calls these measuring blocks, FIS-Control calls them groups, and anything that reads them — a scan tool, a FIS-Control, a logger — needs the same three numbers: the control unit’s address, the group, and which of the four values.

The catch is that the numbers are not written down anywhere official, and a group’s contents change from one engine to the next. This page lists the ones that are dependable, with where each came from.

Which groups can be trusted

From about 1999, Bosch-managed petrol engines were given a standard set: the same group number means the same thing whether the engine is a 1.8T, a VR6 or a 2.0 TFSI. Groups 001–008, 010, 011, 014, 020–023, 031–033, 112, 114–119 and 133 are in it. Those are the most reliable numbers on this page, and the engine-specific ones are extras on top of them.

Diesels have no such standard, but Bosch EDC15 and EDC16 TDIs agree on the handful of groups everybody uses — idle, air mass, boost, injection limits and smooth running. Gearboxes are the least standard of all: the six-speed wet-clutch DSG is included because its temperatures are the reason most people want a gauge for it, and its group is marked as unconfirmed field order because sources disagree about which temperature is which.

If a value in the tables reads —, the position is not confirmed. The configurator never puts a single-value gauge on one of those; it shows the whole group instead, so the label on the screen is the car’s own.

K-line or CAN

Older cars answer on the K-line through the diagnostic connector. Later ones answer over CAN, and FIS-Control treats the same address reached over CAN as a different control unit, with its own settings — which is why the configurator asks which one it is every time it asks for an address. If a group reads nothing, try the other.

Absolute and gauge boost

The engine reports manifold pressure as absolute: about 1000 mbar with the engine off, because that is the air pressure. Boost as a gauge shows it is that figure minus the air pressure outside. FIS-Control measures the outside air pressure itself and can subtract it, which is what its boost display and the configurator’s boost screens do — so 1800 mbar on the engine reads as 0.8 bar on the cluster at sea level.

The groups

Addresses are the diagnostic addresses in hex, as VCDS shows them: 01 the engine, 02 the gearbox. Control unit 00 is not a car module; it is FIS-Control’s own sensor inputs.