VEMS ECU with motronic(88 or 55pin) are available for many BMW engines (harnesses).

VEMS ECU (EC36+EC18 connectors) can also control any spark ignition engine (for lower price, and very good "versatility").

BMW "engines" (harnesses) with 88 pin motronic connector (eg. M50-vanos, M50-nonvanos, S50 and M52 ...) have reasonable pinouts, eg 6 injectors, 6 ignition, ... , also the harnesses are often in good condition, so the [motronic88] versions are often used.

88 pin connectors have slight mechanical variations, see BmwMotronicConnectorVariants


BMW engine running with VEMS PNP (motronic55 connector)

The old motronic55 connector "engines" (harnesses) are designed with only 2 injector pins (3 injectors connected in parallel)

Beware that a PNP install can only save you from making a harness, the installer MUST still verify the harness, and also some small modifications needed to have a reasonable setup (with stuff that can be done better than originally, or which was missing completely: eg. WBO2, analog TPS, DIS, boostcontrol, launchcontrol input, shiftlight output, etc...)

It's an M20B25 engine (from BMW 325 IX E30 ~1988), but it seems BMW was pretty consistent with the pinout, not many variations

WBO2 on SSC5 male standard pinout (same as audi AAN and 3B):

MAT signal

You can find it in the MAF connector AMP-5 (or 6?) pin female connector.

The pin measures appr 2kOhm vs ground.

(other signals on the same connector:

BMW ECU extra connector pinout:

SSC6 feemale

BMW changes 2008-04-25

That means:


More changes 2008-05-04

h[0]=01 02 04 00 00 20 00 00

Idle air controller

Anyone knows

Gergely Lezsak made a few engines, he wrote some docs too, thanx :

Tacho output for RPM gauge

seems to require inductive pullup (eg. 100 Ohm * 220uH). Does anyone BMW dash RPM-gauge working from "logiclevel" 0/5V or 0/12V output ?

Switch TPS to Variable TPS

The BMW Motronic 1.3/1.0/1.1 TPS connector is the same as the variable TPS ones, the Motronic 1.1 or 1.3 TPS wires all go directly to the Motronic connector, Thus no wire changes are actually needed. And any 5V supply , ground and return signal

can be done within the case.

Do you happen to know which motronic55 pins connect to the variable TPS when a variable TPS is hooked up ?

Stock Configuration

Closed Throttle Input #52

Wide Open Throttle Input #53

Ground goes to common ground S701

  1. 53 or #52 are 5v and Signal when used with a variable tps,
I canīt remember wich is signal.

Do you know part numbers for the variable TPS?

E36 BMW one for instance

I guess it's not mechanically (or even pinwise?) compatible with the [certain Bosch TPS]

opinions from Emil:

It is not worth to invest time into these bmw units, as almost everything has to be rewired anyway

injectors are driven 3 at a time, to upgrade injectors its recommended to use one at a time. Also the TPS thingy, WBO2, air temp etc. Will end up into a harness explosion (yes, i have tried, built a pnp for these cars 2 years ago or so..

You will need to route multiple wires from ecu anyway, which will be more time consuming than building a custom harness.

I think the time rather should be invested in getting it working for the E36 and E34, 24 valve engines which already have the features we need in the harness.



Agreed, time would be better spent into building complete harnesses for these cars. Where all the new items would be incorparated and allow 100% use of the stock C101 connector.