Renault Trafic non runner

Towed to us as non runner and the immo light on dashboard stays on all the time.

Firstly plugging in a diagnostic tool gave us no faults but it did fail to communicate with several modules.

All the modules communicate on the canbus network, with specialist equipment we can look at these and see how they are. Below is what we saw on this vehicle and below that what we should see

So we know now that the canbus network is at fault, but where is the difficult part, it could be a faulty component dragging signal down or wiring.

The first thing we did is disconnect as many components as we could on the cambus lines like airbag, radio, cluster, ABS to see if it was a component fault, in this case fault remained. After removing one of the plugs from the ECU the signal did clean up but we still couldn’t communicate with various modules.

Tracing the wiring from this plug through the engine bay we discovered shorted wiring in the loom.

Once wiring was repaired we had comms with most modules apart from engine ECU. A check was made of all the powers and grounds to the ECU all were ok.

So the short on the wiring has caused damage within the ECU.

A new ECU was not a viable option due to cost so a 2nd hand one was sourced and we have the tooling to Virginise the replacement unit and code to the vehicle.

Another Renault saved from the scrap yard!!