Hi all. I’m hoping to find some knowledge here that can help me solve an ongoing intermittent problem with my LF45 150 2005 truck. On some occasions the engine will rev up when braking which is a bit worrying. There is no pattern, wet/hot/cold conditions, long/short runs etc it just seems completely random. There are never any fault codes logged which means that the workshops that I have tried (including DAF) to get it solved have not been able to solve or replicate the fault. When I bought the truck it ran fine for several hours and then started cutting out. DAF could not find a problem but I removed the engine ECU and sent it off for testing - it was toast and not repairable so I bought a second hand one, fitted it myself and had to have it coded by DAF (rippoff). THis fixed the cutting out problem but not the revving up when braking problem. The other slightly odd thing it does, which is possibly related, is that when cruising at limiter speed it will sometimes ‘hunt’ and speed up itself beyond the 90k limit. Its a nice truck apart from these issues and runs very well, I don’t want to sell it and anyway I wouldn’t be happy to sell it on knowing that it has these faults as it could be dangerous. If anyone has had any experience of something similar please could you advise how your problem was solved so I can discuss it with my local workshop.
Many thanks
Craig
Sounds like a wiring fault and it’s either shorting or some water running on to the wiring when you brake. Check the look thoroughly particularly where it bends to go into the cab.
Many thanks for your reply. One of the local workshops suggested a wiring fault was the possible cause and carried out a visual inspection of the loom. I have also thoroughly inspected it myself as well as checking and cleaning all the bulkhead connectors. The next step would be to have an auto/truck electrician carry out more thorough testing although due to the intermittent nature of the faults I am not confident that anything would be found. Its also an expensive process. If no other suggestions are made then I guess I will need to go down that route. Thanks again for your input.