Because wiring can vary slightly by model year and region (e.g., Euro 3 vs. Euro 4 versions), always consult a specific vehicle service manual. You can find detailed PDF versions of these diagrams on platforms like Scribd or Pinterest which often host original workshop manual excerpts.

Note: Pin numbering is usually embossed on the connector housing. Always verify with your specific ECU part number, as minor variations exist across vehicle models and years.

Always disconnect the battery negative terminal before probing the ECU harness. Use a high-impedance multimeter or oscilloscope; do not use a test light on ECU pins.