MOT Failure any ideas???

Hi Guys,
Well took her up for her diagnostic check this morning. Still no further forward!!! They could not get any readings from the car through T4! Obviously a dodgy connection somewhere. Have any of you lot heard of this in the past? Is there a common cause for this. I've checked fuse 33, and also dropped the socket in the footwell, and both look ok, obviously without use of a scanner i won't be able to tell if im getting anywhere. just to confirm, there are only 10 wires from the socket, rather than 16?

AS you have had parts on and off you will need to do an Adaptive Re-set with TestBook or Auto/L rovecom. If you are booked into the Stealer they should have TestBook, ask for the Adaptive re-set and a MAF test to check the air ratio (test book will give the values required, 25-30 KGs at 650 revs if I remembr, but they will know), its ajustable but you need the diagnostic running at the same time to do this - don't try at home. They should also reset the idle and one or two other tests inc lamdas, cats if there are other faults found eventually ending with another Adaptive reset (way I do it) just to make sure.
Also you say the manifold is dull? Do you mea:crazy_driver:n the welding hasn't quite worked fully - my advise is get it off and properly fixed or replaced before the diagnostics.

Well I was putting this reply up as your new message about the Stealer not being able to connect with T4 TestBook. They must be a dim lot not knowing what to do when this happens. The most common reason for no connection the the engin ECU is corrosion in the white plastic connectors that are behind the trim of the lower footwells (just ahead of the doors) on the drivers side its just forward of the bonnet release. The plugs fur up and the connectors go green so its best to do away with the plugs and solder each wire and protect with heat shrink tube. Do both sides of the car, on the passenger side ther are more ECU's. You will find there are two white ones each side - do the bigger ones the smaller is the door speakers. There is also a black plug that does the blower motors that sometimes goes too. All this is caused by cheep plugs in a damp place - Accountants!
p.s. Low battery voltage can also cause no connection.

stopover said:

AS you have had parts on and off you will need to do an Adaptive Re-set with TestBook or Auto/L rovecom. If you are booked into the Stealer they should have TestBook, ask for the Adaptive re-set and a MAF test to check the air ratio (test book will give the values required, 25-30 KGs at 650 revs if I remembr, but they will know), its ajustable but you need the diagnostic running at the same time to do this - don't try at home. They should also reset the idle and one or two other tests inc lamdas, cats if there are other faults found eventually ending with another Adaptive reset (way I do it) just to make sure.
Also you say the manifold is dull? Do you mea:crazy_driver:n the welding hasn't quite worked fully - my advise is get it off and properly fixed or replaced before the diagnostics.

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Hi, the problem is, the dealer can't get T4 to communicate with the car, so can't do an adaptive reset. Do you know of any common faults which can cause this? Water ingress somewhere maybe? Fuses and Connector both look ok. Dealers advise was to book it in for a couple of hours to see if they could find out why they could not connect, which i'd of course much rather try and sort myself. Only problem being, how will i know (without T4/Rovacom etc) that i've fixed it . Could the plug pins be individually tested with a multimeter?

see my edited previous post

stopover said:

see my edited previous post

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Thanks for this. I will go out and start checking/cleaning connectors. I take it there is no way to check other than with T4/Rovacom that the connections are now ok? (I only have a multimeter, don't have scanner).

Hope this works - have pics of one I did recently, note the green areas, the pins inside have corroded away.

And there is no way of knowing if it will work! - obviously if you find pins like this and solder the cheepo plastic plug out the chances of it working are high. I recommend you cut and re-solder one wire at a time, cut as close to the plug as possible as there is not much wire to play with also recommend knee pads! If the plug looks Good then spray with switch cleaner and re-connect then test each wire through the switch with your tester - but I highly recommend soldering it out so no probs in the future. Another thing you can check. The plastic door plate (as you step into the car there is a plastic strip running along the sill just inside the door, it pulls up and you will see the wiring loom going from the front of the car to the BECM under your seat. Make sure this channel is free of water.
I would definately recommend finding an independant chap with a diagnostic such as T4 Autologic or Rovercom in your area. I have suggested to the forum that it would be a great idea to have a registr of such people, we are a lot cheaper than the Stealers (or should be). I have made quite a few friends with P38s and we often help each other out. You can never learn too much with these cars, I hope you stick with it as its a great drive and a lot of satisfaction when you do crack it.

Kraig said:

Was back in at the MOT station today (independant)

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Thats good i took mine to Quickfit (had free MOT with insurance) an they came back with a two page long list of FAILS!! so i took it to a proper MOT place an they passed it without me doing anything!

Couldnt believe it!:alien:

from the readings high co and low lambda it leans towards lambda sensors fault doesnt mean the sensors though had a 4.0td5 in recently that the guy had shelled out 1800 quid at the stealers new sensors/cats/coolant sensor and crank sensor still not fixed it and they still charged him ,turned out to be a fuse,24 i think it was in engine bay ,might be reason for no comunication aswell

Just thought of something else. Underneath the front of the engine bay fusebox there is an earth point, if this is loose or bad then you won't be able to communicate with the engine ECU. Best is to take off the nut and clean it and the connectors going to it with some emery paper. Make sure its tight but not too tight as its small and easily overtightened which strips the thread, which you don't want. If you are doing the plastic plugs do this one also to make sure. Test every fuse (engine bay and under seat) before going back to the Stealer. Please let us know how you get on

Many thanks for all the responses. Stopover, they pictures are spot on cheers for this. I have not yet had a chance to get a look at the connections. But i have Rovacom coming this week so as soon as it comes, i will post the results.

Well, i think the Dealer was trying to con me out of extra cash. Rovacom arrived today, plugged it in and straight away it worked! The fault that was coming up is Oxygen Sensor on Bank 2. Reset the fault and done an adaptive reset. Then checked the inputs when running, no signal from oxygen sensor. Have a new one arriving first thing tomorrow, and then a retest Friday, so hopefully that should be it sorted, i will post the result on Friday when i find out. Thanks for all the suggestions and replys guys.

MORE HELP PLEASE!! Well, finally got back under the car today. Replaced Cats and both Lambdas, (I threaded the original downpipes, so had to replace the Cats!) then done an adaptive reset of the ECU. Big problems now, Car struggles to Idle when warmed up. Start the car from cold it will idle ok, once warm any revs and the car cuts out. Try to restart and it needs to be revved, and then slowly reduced to make it idle. Took it for a spin, maybe 2 -3 miles, slowed down to idle and the car cut out. Managed to start it again, drove it home, ready to select reverse and again it died. Once parked up, had a quick look at the Adaptive Values (Settings) in Rovacom, and there is no Air Flow Value, yet checking the Air and Idle Inputs and it is getting 21kg of flow. Both lambdas are now getting Voltage readings and the fuel trim on Bank 2 has reduced from + readings down to exceptable - readings. Just to confirm when running/driving, both lambdas have different readings?

Kraig said:

the fuel trim on Bank 2 has reduced from + readings down to exceptable - readings.

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the fuel trim on Bank 2 has reduced from + readings down to acceptable - readings. :doh: