Recently, I have had all sorts of problems with my Autotrail Cheyenne 2008 (58) on a Fiat Ducato Chassis, so I thought as these vehicles and chassis are used by various manufacturers I should post the issues as the cost were and can be very expensive.
In December 2017 the engine warning light appeared so off to my local garage to investigate.
It seems that the Lambda sensor had failed according to the Diagnostics kit. £400.00 later what with the part and labour costs, I was off on my travels happy that was the problem resolved never to come back!!
All seemed OK until two weeks ago when as we left home for a weekend away the Engine light came on again, we decided we would get it checked out on our return on Monday. So off to my garage again and connected to the Diagnostics kit over 20 fault codes came up.
Lambda, Throttle Body, Air-con pressure sensor and 17+ other faults. The mechanic first found that the multi-plug on the engine wiring loom was completely corroded, so after replacing that just 3 faults came up: Lambda, Throttle and Air-con pressure.
The Lambda sensor was replaced again this leaving just the other two, they tried to find a new Throttle Body but when the replacement came it was the incorrect one as although this was the part Fiat had supplied for my vehicle it appeared that old stock had been used on my MH when new and the TB that was fitted was from an earlier model.
So a search was carried out, none in the UK and couldn't find one in Europe, I had seen prices being charged for these TB's from £600 to £1200 so was getting quite concerned.
As a stop gap the mechanic decided to clean up the old TB and refit it until a replacement could be found. The face of the TB was completely rusted stopping the motor arm that assesses the amount of fuel to push into the engine from working correctly.
After complete grinding cleaning and sealing the TB back onto the engine all the faults cleared. After waiting two more days and constantly checking the engine started without any fault codes I pickup my MH after paying another £650.00.
All these faults were caused because of water entering the engine bay over the 10 years since manufacture. The cause of this water ingress could have been totally prevented either by Fiat or Autotrail.
On the plastic Scuttle panel below the windscreen and just above the bonnet there are drain holes one each side these should drain all the water that runs off the front of the roof overhanging the windscreen and the screen itself.
The one on the drivers side was fine but the drain on the passenger side had NEVER been fitted so just a hole was there with no Drain or pipe fitted, this allowed water to constantly drain down onto the electrics causing the problems with the multi-plug.
The other serious problem was in the middle of the plastic Scuttle Tray where it is joined, as it is in two pieces it had never been sealed so water sitting in this scuttle tray was constantly leaking down the middle onto the engine and of course dropping down onto the Throttle Body and causing the rusting.
This problem caused electrical shorts through the loom system so everything connected through it was effected. Have a look at your MH and just check these two areas as a simple fix/sealing now could save you lots of time and money in the future!