Unknown problem

[henrym3]

Last night I updated my Foxwell 644 scanner and put it on the vehicle today just to check the scanner still worked as expected. Apart from the usual faults which I ignore, under EGS (gearbox) it came up with. "Converter Lock up Clutch, Excessive slip". On further investigation it shows Solenoids 1/2/3/5 pressure 780ma  lock up solenoid 4 (converter lock up) 156ma. Should I be worried? I am not aware of any gb problems, doesn't seem like it's slipping.

[X5Sport]

All .I can tell you from my experience is that it was the TC lockup clutch that failed, blocked of oil pump feed and that was the end of the gearbox.  There was no warning, no change in how the car was running and no warning lights.  One minute it was fine and then it needed a full rebuild.

[henrym3]

So, just what I need before xmas, is a replacement/new/ TC likely to be all that's wrong at the moment. I thought TCs were pretty bullet proof.

[X5Sport]

Unfortunately not.  TC failure is also common - and cheaper than a rebuilt box.  New ones are about £250 plus fitting.

[henrym3]

Should have mentioned that I also have an intermittant fault on front left wheel sensor. Part arrived today to be fitted at the weekend. Anyway, phoned some g/b people mentioned both faults and was told that the sensor played no roll in the g/b fault. They would start with changing the TC £700+VAT, if that didn't cure it they would look inside box at solenoids. So in other words keep changing things until the fault goes away. Seems an expensive way to go about things. Seeing as X5Sport said a TC was around £250 that seems expensive to change it. Anyway at those prices I think I'll have a fiddle myself, I could buy an awful lot of bits for that money.
Question:-The TC lock up clutch must be done electrically when certain parameters are met. What are those parameters and where does it get it's information from?

[Horizon]

[quote="henrym3"]
Should have mentioned that I also have an intermittant fault on front left wheel sensor. Part arrived today to be fitted at the weekend. Anyway, phoned some g/b people mentioned both faults and was told that the sensor played no roll in the g/b fault. They would start with changing the TC £700+VAT, if that didn't cure it they would look inside box at solenoids. So in other words keep changing things until the fault goes away. Seems an expensive way to go about things. Seeing as X5Sport said a TC was around £250 that seems expensive to change it. Anyway at those prices I think I'll have a fiddle myself, I could buy an awful lot of bits for that money.
Question:-The TC lock up clutch must be done electrically when certain parameters are met. What are those parameters and where does it get it's information from?
[/quote]
Regarding the wheel sensor and gearbox TC lockout, I'm sure I saw a wiring diagram somewhere on the internet, that the speed sensors on the gearbox fed information into the same module as the wheel sensors. This was done to assist in the decision to what was the best gear to be selected , so could be linked

[henrym3]

I will admit my knowledge in this is limited, (read non existent)and I have harboured the wild hope that somehow the two were in some way interlinked. I will certainly report one way or the other after I have fitted the new sensor at the weekend. Horizon you have raised my hopes to a new level.

[henrym3]

Fitted new sensor today, what a nightmare, remove allen screw and pull out sensor, snap 2 hours later I get it out. Would have been quicker to remove drive shaft but had loaned my 36mm socket out. Clear fault codes go for long drive and recheck codes, No lock up clutch faults. Can't believe this has cured the problem, have to try and not be paranoid and do scans every 5 mins. Thought that while I was on a roll I'd have a look at the fuel tank vent valve fault I've got, so got really technical and sprayed some WD40 on purge valve pins plugged it in/out several times. Another fault fixed. I need to start another thread for help with remaining faults. Still a good day though.

[Horizon]

Result

[X5Sport]

And this is of course why everyone now struggles to correctly diagnose issues.  The thing I object to most of all is that us as Owners foot the bills for this 'suck it and see approach' involved in changing modules until the error clears.

That's just bad engineering!

[henrym3]

I fully agree and bearing in mind this is a 14 year old car with what would be by today's standards simple electronics I can see why a lot of people keep new for manufacturers 3 year warranty and get rid.