Before commencing any electrical work on a motor vehicle we strongly recommend that the battery is disconnected.

Before fitting an exchange ECU remove any dirt or corrosion that may have built up around the connectors on the vehicle. A stiff nylon brush (such as an old toothbrush) is recommended for this purpose and NOT a wire brush as this may damage the plating and cause reliability problems later.

The use of contact grease for under-bonnet connections can be beneficial providing it is a properly formulated treatment. Ordinary oil or grease should not be used. Electrical contact sprays such as SERVISOL or one of the ELECTROLUBE range can be used on ECU connectors but we do not recommend the use of general purpose silicone lubricants.

Check ECU connections thoroughly for any sign of water ingress, often indicated by white or green corrosion deposits. Locate the source of water leakage and correct before fitting the exchange ECU.