Getting started with the W202 ME2.1 ECU connector This ECU has a CAR connector with 145 pins that you can find it [here](link) How to read the following table: Connector : Connector from A to F on the harness. Pin: Pin number of the connector. Name: this field was filled from the M111.921 wiring diagram. Function: some human readbale text. ME2.1 Description: Based on me2.1 documenation what i have found for Alfa Rome. MRE pin: Where to connect the pin (wiring example). Comments: extra info that i learned during wiring in the ECU. |Connector|Pin Number|Name |Function | ME2.1 Description| MRE pin | Comments | |---------| ---:|:------------- | --------- | -------- |:------------------------------ |--------- | ------------ | | A | 1 | NC | NC | NC | NC | | | A | 2 | 12V ACC | Supply | Supply | MRE pin 1,5 | 12v Supply when ignition is on. | | A | 3 | KL31(GND) | Ground | Ignition earth |MRE pin 2,6 | Supply earth | | A | 4 | NC | NC | NC | NC | | | A | 5 | O2 LSS | O2 Heater | Lambda sensor heater | NC | Only if you plan to use factory NB O2 sensor | | A | 6 | FAN Control | PWM to Fan control module | Relay for 1st Fan Control | MRE pin 33 (GP3) | On some models this is PWM output and SAM ECU controls the FAN based on this. Note a 10hz/30% Duty is neaded to make the ecu happy, higher duty equals higher fan speed. 30% is off. | | A | 7 | KL31(GND) | Ignition Gnd | Ignition earth| MRE pin 2,6 | | | A | 8 | KL31(GND) | Sensors Gnd | Electronic earth (for sensors) | MRE pin 2,6 | | | B | 1 | NC | NC | NC | | | | B | 2 | NC | NC | NC | | | | B | 3 | Diag5 | NC | Programming | NC | | | B | 4 | 12V KL30 | Permanent 12v supply | Battery | | | | C | 1 | NC | | NC | | | | C | 2 | NC | | NC | | | | C | 3 | NC | | NC | | | | C | 4 | NC | | NC | | | | C | 5 | NC | | NC | | | | C | 6 | NC | | NC | | | | C | 7 | NC | | NC | | | | C | 8 | NC | | NC | | | | C | 9 | NC | | NC | | | | C | 10 | NC | | NC | | | | C | 11 | NC | | NC | | | | C | 12 | NC | | NC | | | | C | 13 | NC | | NC | | | | C | 14 | NC | | NC | | | | C | 15 | NC | | NC | | | | C | 16 | NC | | NC | | | | C | 17 | NC | | NC | | | | C | 18 | NC | | NC | | | | C | 19 | NC | | NC | | | | C | 20 | NC | | NC | | | | C | 21 | EVAP Solenoid | Low side switch | Fuel vapour recovery solenoid valve| MRE pin 3 (LS2) | Control this pin via FSIO. | | C | 22 | Supply PPS1 | 5V supply for PPS | Supply for potentiometer - 1 accelerator pedal|MRE pin 44 (5V)|| | C | 23 | GND PPS1 | Ground for PPS | Earth for potentiometer - 1 accelerator pedal |MRE pin 21 (GND)|| | C | 24 | Signal PPS1 | Pedal Position1 | Signal for potentiometer - 1 accelerator pedal|MRE pin 31 (AV3)|| | C | 25 | Signal PPS2 | Pedal Position2 | Signal for potentiometer - 2 accelerator pedal|MRE pin 30 (AV7)|| | C | 26 | GND PPS2 | Ground for PPS | Earth for potentiometer - 2 accelerator pedal |MRE pin 21 (GND)|| | C | 27 | Supply PPS2 | 5V supply for PPS | Supply for potentiometer - 2 accelerator pedal|MRE pin 44 (5V)|| | C | 28 | NC | | Sport throttle response on warning light | | | | C | 29 | Fuel Pump | Low Side switch for FP relay | Fuel pump relay | MRE pin 35 (GP1)| | | C | 30 | NC | | NC | | | | C | 31 | O2 Signal GND | NB Heated O2 Signal GND | Lambda sensor earth | | | | C | 32 | O2 Signal | NB Heated o2 Signal | Lambda sensor signal| | | | C | 33 | NC | | NC | | | | C | 34 | NC | | NC | | | | C | 35 | NC | | NC | | | | C | 36 | NC | | NC | | | | C | 37 | NC | | NC | | | | C | 38 | DIAG | Tacho out | RPM Signal | | I send information over CAN. | | C | 39 | DIAG | K line | Diagnostic connection (line K) | | | | C | 40 | SAM? | | NC | | | | D | 1 | NC | function | MRE pin | Comments | | D | 2 | NC | | Relay for cooling fan 2 nd speed | | | | D | 3 | Starter LSS | Starter Relay| NC | MRE pin - | I use just and external switch. | | D | 4 | NC | | NC | | | | D | 5 | NC | | CAE gear selector switch | | | | D | 6 | NC | | NC | | | | D | 7 | NC | | NC | | | | D | 8 | NC | | NC | | | | D | 9 | NC | | NC | | | | D | 10 | NC | | NC | | | | D | 11 | CAN_H | Can High | CAN line "high" | MRE pin 48 (CANH) | | | D | 12 | CAN_L | Can Low | CAN line "low" | MRE pin 47 (CANL) | | | D | 13 | NC | | Speedometer signal | | | | D | 14 | NC | | Brake lights switch | | | | D | 15 | NC | | NC | | | | D | 16 | NC | | NC | | | | D | 17 | NC | | CAE recognition | | | | D | 18 | NC | | NC | | | | D | 19 | NC | | Clutch Pedal | | | | D | 20 | NC | | Cruise Control + | | | | D | 21 | NC | | Cruise Control - | | | | D | 22 | NC | | Cruie Control recall | | | | D | 23 | NC | | Break Sw | | | | D | 24 | NC | | Cruise Control deactivation | | | | E | 1 | NC | | Operation of injector for cyl. 3 | | | | E | 2 | NC | | Operation of injector for cyl. 6 | | | | E | 3 | NC | | NC | | | | E | 4 | VVT LSS | VVT coil LSS | Air conditioning compressore relay feed | MRE pin 7 (LS1)| On My variant this is VVT, on other OEMs it is compressore clutch. | | E | 5 | NC | | NC | | | | E | 6 | NC | | NC | | | | E | 7 | NC | | NC | | | | E | 8 | NC | | NC | | | | E | 9 | NC | | NC | | | | E | 10 | NC | | Cruise control on warning light| | | | E | 11 | NC | | NC | | | | E | 12 | NC | | NC | | | | E | 13 | Injector 4 | Injector 4 | Operation of injector for cyl. 2 |MRE pin 42 (INJ4) | | | E | 14 | Injector 2 | Injector 2 | Operation of injector for cyl. 5 |MRE pin 38 (INJ2) | | | E | 15 | NC | | Air conditioning pressure switch 1st stage | | | | E | 16 | NC | | NC | | | | E | 17 | Oil Switch | Oil Level Switch | Air conditioning pressure switch 2nd stage | MRE pin | In case this is used, it must be connected to a temperature input. This way we have a pull up inside MRE and this switch would drive the line low. | | E | 18 | NC | | NC | | | | E | 19 | NC | | NC | | | | E | 20 | NC | | NC | | | | E | 21 | NC | | Air conditioning request switch | | | | E | 22 | NC | | NC | | | | E | 23 | NC | | Sport throttle response switch | | | | E | 24 | NC | | Sport throttle response switch earth | | | | E | 25 | Injector 1 | Injector 1 | Operation of injector for cyl. 1 | MRE pin 37 (INJ1)| | | E | 26 | Injector 3 | Injector 3 | Operation of injector for cyl. 4 | MRE pin 41 (INJ3)| | | E | 27 | NC | | NC | | | | E | 28 | CLT GND | Signal GND | Coolant temperature sensor earth | MRE pin 21 | | | E | 29 | CLT Signal | CLT Signal | Coolant temperature sensor signal| MRE pin 18 (AT1)| | | E | 30 | NC | | NC | | | | E | 31 | TPS1 | TPS1 signal |Potentiometer - 1 butterfly casing| MRE pin 26 (AV2)| | | E | 32 | TPS GND | TPS GND |Earth for potentiometer 1-2 butterfly casing | MRE pin 21 | | | E | 33 | TPS Supply | 5V TPS supply | Supply for potentiometer 1-2 butterfly casing|MRE pin 44 (5V)| | | E | 34 | TPS2 | TPS2 signal | Potentiometer - 2 butterfly casing | MRE pin 28 (AV10) | | | E | 35 | NC | | NC | | | | E | 36 | NC | | NC | | | | E | 37 | CKP- | VR- | Rpm sensor (-) | MRE pin 46 (VR-)| | | E | 38 | CKP+ | VR+ | Rpm sensor (+) | MRE pin 45 (VR+)| | | E | 39 | CAM- | CAM Sensor GND | Timing sensor earths| MRE pin 21 | CAM supply in factory harness 12V | | E | 40 | CAM+ | CAM Signal | Timing sensor signal | MRE pin 25 (CAM) | | | E | 41 | KNOCK- | |Earth for detonation sensor 1 (cylinders 1-4-5)| MRE pin | | | E | 42 | KNOCK+ | |Signal for detonation sensor 1| MRE pin | Usable with diy external circuit. | | E | 43 | NC | |Earth for detonation sensor 2 (cylinders 2-3-6)| | | | E | 44 | NC | |Signal for detonation sensor 2 | | | | E | 45 | MAF Pin 1 | IAT Signal | Air temperature sensor | MRE pin 23 (AT2)| | | E | 46 | MAF Pin 4 | 5V Supply | Flow meter - reference voltage 5V | MRE pin 39| | | E | 47 | MAF Pin 5 | MAF Signal | Output voltage (signal) - flow meter |MRE pin 24 (AT3) | | | E | 48 | MAF Pin 3 | Signal GND | Earth - flow meter | MRE pin 21 | | | F | 1 | ETB- | | Butterfly casing motor integrated with D.V.L. (-) |MRE pin 8 (ETB-)| | | F | 2 | ETB+ | | Butterfly casing motor integrated with D.V.L. (+) | MRE pin 4 (ETB+)| | | F | 3 | NC | | NC | | | | F | 4 | NC | | NC | | | | F | 5 | NC | |Operation of ignition coil for cyl. 6 | | | | F | 6 | NC | |Operation of ignition coil for cyl. 2 | | | | F | 7 | NC | | NC | | | | F | 8 | NC | | Earth | | | | F | 9 | NC | | NC | | | | F | 10 | NC | | NC | | | | F | 11 | NC | | NC | | | | F | 12 | NC | | NC | | | | F | 13 | IGN1 | | Operation of ignition coil for cyl. 4|| OEM coils cannot be used without external igniter!! | | F | 14 | NC | | NC | | | | F | 15 | KL31 (GND) | | NC | | | | F | 16 | NC | | NC | | | | F | 17 | NC | | Operation of ignition coil for cyl. 3 | | | | F | 18 | NC | | NC | | | | F | 19 | NC | |Operation of ignition coil for cyl. 5| | | | F | 20 | IGN2 | |Operation of ignition coil for cyl. 1| | | | F | 21 | NC | |Operation of injection warning light| | |