Ever wondered what happens when you continually park under that lovely shady tree? You know, the one that unfortunately drops leaves, nuts and twigs onto your car? Over time, you will find that the vegetative debris from that beautiful tree will eventually build up and may block the windscreen plenum drain offs. These drain offs are positioned on both sides of your vehicle, below the windscreen, and are there to deal with large amounts of rain that need to be directed away from vital electrical and mechanical components.
The photos attached are a good example of the ramifications of this build up. When the rain has nowhere to run, it pools up then eventually flows into nearby areas, thus flooding them one by one. Even though this engine ECU was relatively isolated in a plastic housing, the water still managed to make its way in and started to fill the ECU housing, thus immersing the ECU in water.
Fortunately we were able to catch this in time. The symptom that the vehicle was suffering from was an intermittent engine misfire and stalling. Thanks to our highly trained technicians and our new ‘Diagnostic Suite’ that has been recently installed here at Pace, we were able to trace the issue back to the source. From there it was a case of removing the ECU, splicing the casing open and cleaning up some mild corrosion on the circuit board. After reassembling the components and erasing the related fault codes, a perfect result was achieved and this BMW 135i was back to its bristling self again.