Digital Motor Electronics [DME]

Changes Compared to the Previous Digital Motor Electronics [1][2]DME M1.7, 12- Cylinder M70

M1.7 M70 M5.2 M73

No knock control 2 knock sensors per row of cylinders

1 inductive pulse generator 1 Hall sensor (camshaft sensor) on camshaft of cylinder row cyl.1...6
(cylinder reference sensor)
at ignition lead, cylinder 6

2 air mass meters 2 hot-film air mass meters

1 intake air temperature sensor per 1 intake air temperature sensor (for cylinder row, cyl. 7...12)
row of cylinders

2 engine temperature sensors 1 engine temperature sensor on cylinder row, cyl. 1 ...6
in one joint housing

1 tank ventilation valve per row of cylinders 1 tank ventilation valve per row of cylinders "closed with no power applied".
"open with no power applied" as soon as
vacuum builds up in intake system and the
mechanical non-return valve opens

1 oxygen sensor per row of 4 oxygen sensors: 1 oxygen sensor per row of cylinders before and after the catalytic converter
cylinders ahead of catalytic converter- New spark plugs and smaller, lighter ignition coils

Speed signal from instrument cluster Speed signal from ABS/DSC control unit

No secondary air pump 1 secondary air pump to improve exhaust gas at cold start

1 fuel pump and one EKP relay 1 fuel pump and 1 EKP relay activated by both DME control units
per row of cylinders

No CAN-bus Data exchange between DME control units via CAN-bus

No automatic start Automatic start. If the [1][2]DME detects a signal from terminal 50, the starter relay is activated directly by the DME control unit. The relay is triggered once the engine has started (detection via speed signal).

DME Control Units
2 DME control units operate in this system. The DME control unit I supplies the of cylinders 1 (cylinders 1. .6), the identical control unit supplies the row of cylinders II (cylinders 7...12). For the purpose of differentiation in diagnosis mode, Pin 48 on control unit II is connected to ground. Relevant components are mostly installed in duplicate. Exceptions are:

- Start relay
- Start lock-out relay
- Camshaft sensor
- Intake temperature sensor
- Engine temperature sensor
- Secondary air pump
- Electrical fuel pump
- EKP relay (electrical fuel pump)

The DME control units are connected with following systems:
- Adaptive transmission control AGS
- Electronic throttle control EML
- Dynamic stability control DSC
- Instrument cluster electronics IKE
- Central body electronics ZKE
- Antitheft system DWA via ZKE
- Multi-information display MID via IKE

The digital motor electronics [1][2]DME undertakes following functions:
- Cylinder-individual injection with correction feature
- Ignition
- Ignition circuit monitoring
- Cylinder-selective, adaptive knock control with 2 sensors per row of cylinders
- Idle control via throttle valves of electronic throttle control EML
- Lambda control
- Load setting via hot-film air mass meter HFM
- Incremental system for engine speed and reference mark signal
- Cylinder reference by inductive pulse generator on camshaft gear
- Electrical fuel pump activation (EKP) with safety lockout function at speed zero
- Characteristic map-control led tank ventilation
- DSC engine intervention (dynamic stability control)
- Drive-away protection via antitheft system (DWA), multi-information display MID or electronic drive away inhibit EWS
- Characteristic map programming
- Idle CO adjustment (vehicles without lambda control)
- Secondary air pump control
- Interface to AGS via CAN (Controller Area Network) data bus
- Ignition timing (angle) intervention by adaptive transmission control (AGS)
- Self-diagnosis and emergency operation characteristics

The EML undertakes following functions:
- Engine speed limitation
- Speed limitation by V-signal
- The idle system is controlled by the [1][2]DME and carried out by the EML by correspondingly positioning the throttle valve.
- Maximum speed limitation takes place directly by reducing the throttle angle.