Audi A2 Conversion
On this page we describe the conversion of an Audi A2 1.4i petrol to electric propulsion. We will use the following components:
- Nissan Leaf 24 kWh battery pack with original BMS
- Toyota Prius Gen 2 (2004-2009) transaxle with matching inverter
- openinverter Prius Gen2 motor controller
- openinverter main board running stm32-car (VCU in ECU enclosure)
Pin mapping
We start out by mapping out useful pins of the original wire harness
ECU
The ECU has two connector slots, a smaller one with pins 82-121 and a larger one with pins 1-81. Here we map out pins useful to us

| # | orig function | our function | wire color |
|---|---|---|---|
| 1,2 | GND | ||
| 3 | permanent 12V | ro | |
| 4 | ignition 12V | ||
| 5 | Lambda (first) heater | gr | |
| 28 | From generator (maybe DF) | li/bl | |
| 40 | To Climate control display | sw/ge | |
| 41 | To Climate control display | sw/gr | |
| 51 | Lambda (first) signal | bl/ws | |
| 52 | Lambda (first) signal | ge | |
| 63 | Lambda (second) heater | li/ro | |
| 64 | Charcoal filter solenoid | bl/ge | |
| 65 | Fuel pump relay- control | ro/br | |
| 68 | Lambda (second) signal | bl/br | |
| 69 | Lambda (second) signal | ro/li | |
| 70 | Lambda (first) signal | bl | |
| 71 | Lambda (first) signal | sw | |
| 88 | Injector 3 | sw/li | |
| 89 | Injector 4 | li/sw | |
| 96 | Injector 1 | br/bl | |
| 97 | injector 2 | sw/gn | |