This car came to me on a truck this morning as a No Crank No Start. Initial Diagnosis was No Communication with Engine, Auto Gear Control, ABS, Power Steering, Electric Park Brake and others. Quick Conclusion was that the High Speed CAN Network was dead.
Customer tells me he heard a Whistling / Whooshing Noise then the car died.
Very quickly I could see that the Insulation around the Wiring Loom at the front of the engine, in between the 2 Arrows below was damaged.
A quick feel revealed that the loom had got hot on the underside and some wires and insulation had melted together.
Some 10 - 12 wires were damaged, the two Blue & White Can Lines included. I have repaired the loom and now have Global Communication and the Engine will start and run but I can hear that Loud Whistling Whooshing Noise - Not Good !!
Below that part of the loom is a Rubber Pipe from DPF to DPF Pressure Sensor which has a hole burnt through it. Now we know how the loom sustained damage.
Now the part that makes no sense to me
This Engine is running only because it can exhale its Exhaust Gasses through the Break in the small rubber pipe, I held my hand over the tail pile and felt "Nothing" yet I could hold my hand a good Meter Away from the split in he Pipe and could feel and smell the exhaust gasses.
My Confusion :
This man was lucky because the heat damaged the HS CAN Lines first and Cut the Engine.
The DPF must be completely Blocked, I cold not feel a thing at the tail pipe. It would not blow a piece of tissue out !!
I have since googled this issue and all I can find is that these cars have a habit of catching fire but nobody knows why, It could be that if they do catch fire then it would be difficult to establish the root cause.
With that degree of DPF blockage, How did this Engine Continue to Run, Not Checked yet but the insides of the DPF Pressure Sensor must be Ruined / Burnt / Obliterated, The Sensor Must be the weaker link up against the Rubber Pipe that gave up and melted ???