Me7.4.5 Pinout May 2026

✅ Battery disconnected
✅ ME7.4.5 pinout printed and verified with vehicle year
✅ All grounds (pins 1, 3, 70, 71) secured to clean metal
✅ +12V permanent (pins 4, 72, 73) and switched (5, 69) present
✅ CAN bus (6,7) resistance approximately 60 ohms between pins
✅ Fuel pump relay control (19) connected correctly
✅ No bent pins inside the T121 housing

Below is the definitive pinout for the ME7.4.5. Pins are numbered 1 through 121. Pins marked “---” are unused in most manual-transmission 1.8T applications.

| Pin | Connector | Signal Name | Description | Typical Function | |------|-----------|----------------|--------------------------------|--------------------------| | 1 | A | Ground | Sensor ground | - | | 2 | A | EVAP Canister Purge Valve (N80) | Duty cycle control | Emissions | | 3 | A | Ground | Power ground for injectors/coils | - | | 4 | A | +12V Battery | Permanent power (Terminal 30) | ECU memory | | 5 | A | +12V Switched (Terminal 15) | Switched via ignition | Wake-up signal | | 6 | A | CAN-High | Drivetrain CAN bus | ABS, Instrument cluster | | 7 | A | CAN-Low | Drivetrain CAN bus | ABS, Instrument cluster | | 8 | A | Brake light switch signal | Input | Brake pedal | | 9 | A | Clutch pedal switch | Input | Cruise control / starting | | 10 | A | A/C compressor request | Input | Climate control | | 11 | A | Radiator fan activation (low speed) | Output | Cooling | | 12 | A | Radiator fan activation (high speed) | Output | Cooling | | 13 | A | --- | Not used | - | | 14 | A | Alternator excitation signal | Output | Charge warning | | 15 | A | Diagnostic K-Line (ISO 9141) | Bi-directional | OBD2 communication | | 16 | A | --- | Not used | - | | 17 | A | --- | Not used | - | | 18 | A | --- | Not used | - | | 19 | A | Fuel pump relay control | Output | Activates FP relay | | 20 | A | Engine speed output (RPM signal) | Output | Tachometer cluster | | 21 | A | MIL (Check engine light) | Output | Warning lamp | | 22 | A | EPC light | Output | Electronic Power Control | | 23 | A | +5V Sensor supply | Reference voltage | For MAP, TPS, etc. | | 24 | A | --- | Not used | - | | 25 | A | --- | Not used | - | | 26 | A | --- | Not used | - | | 27 | A | --- | Not used | - | | 28 | B | Knock sensor 1 (cyl 1 & 2) | Signal input | Ignition timing control | | 29 | B | Knock sensor 2 (cyl 3 & 4) | Signal input | Ignition timing control | | 30 | B | Sensor ground (shield) | For knock sensors | - | | 31 | B | Intake Air Temp (IAT) | Signal input | Inside MAF or TMAP | | 32 | B | Engine Coolant Temp (ECT) | Signal input | Temperature compensation | | 33 | B | Shield ground | For crank/cam sensors | - | | 34 | B | MAF signal | Frequency/duty cycle | Airflow metering | | 35 | B | MAF ground | Sensor return | - | | 36 | B | G28 Engine speed (crank sensor) | Differential signal (-) | RPM base timing | | 37 | B | G28 Engine speed (crank sensor) | Differential signal (+) | RPM base timing | | 38 | B | G40 Camshaft position sensor | Hall effect signal | Sequential injection | | 39 | B | Throttle position sensor (G187) | Signal 1 (closing) | ETC | | 40 | B | Throttle position sensor (G188) | Signal 2 (opening) | ETC redundancy | | 41 | B | Accelerator pedal position (G79) | Signal 1 | Driver demand | | 42 | B | Accelerator pedal position (G185) | Signal 2 | Redundant signal | | 43 | B | MAP sensor (Integrated) | Boost pressure signal | Inside ECU case | | 44 | B | MAP sensor ground | Internal ECU | - | | 45 | B | External MAP (for some models) | Boost input (rare) | - | | 46 | B | --- | Not used | - | | 47 | C | Injector cylinder 1 | Output (ground switch) | Fuel delivery | | 48 | C | Injector cylinder 2 | Output (ground switch) | Fuel delivery | | 49 | C | Injector cylinder 3 | Output (ground switch) | Fuel delivery | | 50 | C | Injector cylinder 4 | Output (ground switch) | Fuel delivery | | 51 | C | Ignition coil 1 (power stage) | Output | Spark | | 52 | C | Ignition coil 2 (power stage) | Output | Spark | | 53 | C | Ignition coil 3 (power stage) | Output | Spark | | 54 | C | Ignition coil 4 (power stage) | Output | Spark | | 55 | C | N75 Boost control valve | PWM output | Wastegate control | | 56 | C | Idle Air Control (N71) | PWM output (if not DBW) | Idle stabilization | | 57 | C | Secondary air injection pump relay | Output | Cold start emissions | | 58 | C | Secondary air injection valve (N112) | Output | Air diverter | | 59 | C | O2 sensor heater (Bank 1, Sensor 1) | Output | Lambda heating | | 60 | C | O2 sensor heater (Bank 1, Sensor 2) | Output (post-cat) | Heating | | 61 | C | O2 sensor (Sensor 1) signal | Input (0-1V or wideband) | AFR | | 62 | C | O2 sensor (Sensor 1) ground | Ground for lambda | - | | 63 | C | O2 sensor (Sensor 2) signal | Input | Post-cat monitoring | | 64 | C | O2 sensor (Sensor 2) ground | Ground | - | | 65 | C | Fuel tank pressure sensor | Input | Leak detection | | 66 | C | --- | Not used | - | | 67 | C | --- | Not used | - | | 68 | C | --- | Not used | - | | 69 | A | +12V Switched (Terminal 15) duplicate | Redundant | Safety | | 70 | A | Ground | Power ground | High current | | 71 | A | Ground | Power ground | High current | | 72 | A | +12V Battery duplicate | Redundant main power | - | | 73 | A | +12V Battery duplicate | Redundant main power | - | | 74-121 | --- | Various unused or vehicle-specific pins | (e.g., cruise control, A/C pressure) | Check wiring diagram |

Disclaimer: Pins beyond 74 are often empty on manual 1.8T ME7.4.5 ECUs. For A/T cars, pins 84-89 may carry TCU CAN data. me7.4.5 pinout

The ME7.4.5 is a "torque-based" ECU, meaning it uses complex calculations between throttle position, airflow (MAF), boost pressure, and ignition timing. If any sensor signal is interrupted or shorted due to incorrect wiring, the ECU will immediately pull timing and limit boost. In short: correct pinout = correct performance.

Whether you are:

…you will need a reliable ME7.4.5 pinout diagram. ✅ Battery disconnected ✅ ME7

The ME7.4.5 uses a single, massive 121-pin connector, commonly referred to as the T121 connector. However, in practical terms, the T121 is divided into three separate physical plugs labeled A, B, and C. Each plug has a different number of pins and distinct color codings depending on the vehicle, but the pin functions remain consistent across most 1.8T 20V engines (AUG, AUM, BAM, AMK, APX codes).

Note: Some variant ECUs (like for automatic transmissions) may have extra pins for TCU communication. The manual transmission pinout is covered here.

| ECU Version | Key Differences | |-------------|------------------| | ME7.4 | Older, less memory, slower processor | | ME7.4.5 | Drive-by-Wire (ETC), wideband oxygen sensor (LSU 4.2) | | ME7.5 | Different pinout (T94 connector, not T121) | Disclaimer: Pins beyond 74 are often empty on manual 1

Never mix ME7.4.5 pinout with ME7.5 – they are physically incompatible.

When performing an engine swap (e.g., fitting a 1.6 16V TU5JP4 engine into a different chassis), the ME7.4.5 harness is often retained. Key challenges include:

| Pin Number | Pin Name | Description | | --- | --- | --- | | 10 | CKCP | Crankshaft position sensor | | 20 | CAM | Camshaft position sensor | | 30 | INJ1 | Fuel injector 1 | | 40 | IGN1 | Ignition coil 1 |