Rover 75 diesel nearly 103000 miles lost temperature gauge and rear screen heater

[grahamw]

At least the problems are becoming less serious..
But this wonderful motor car of ours is still taking up every day off I've got!
Rear screen heater stopped working first, (Light doesn't come on, no demist)
Then today the temperature gauge ceased to move.
Hope it's not a sign of things to come. I'll start work in the morning and post any updates.
Graham.

[T-Cut]

Then today the temperature gauge ceased to move.


Has it not moved from the 'off' position? If so, the coolant temperature sensor signal has been lost. Usually caused by faulty connector or wiring to the connector. This normally causes the radiator fan to trip on at high speed. Diesels run rather cool, so the gauge may not reach the 'normal' mark. Does it appear to be warming up as usual? What's the typical running temperature (via the diagnostic screen)?

TC

[maxxpump]

At least the problems are becoming less serious..
But this wonderful motor car of ours is still taking up every day off I've got!
Rear screen heater stopped working first, (Light doesn't come on, no demist)
Then today the temperature gauge ceased to move.
Hope it's not a sign of things to come. I'll start work in the morning and post any updates.
Graham.

I would check the passenger side plenum for water ingress, as this can be a early warning sign of a water logged ECU!

Could just be a electrical fault elsewhere in the system but I would check there first!

[cb750chris]

I would check the passenger side plenum for water ingress, as this can be a early warning sign of a water logged ECU!

Could just be a electrical fault elsewhere in the system but I would check there first!

I would suggest this is the first place to start too. Loosing 1 of these might lead me to look at the circuit in question, but the ECU deals with these signals (and more) - The engine temperature is supplied form the ECU to the instrument cluster. It also tells the climate control the engine is running (somehow...) so the heated rear window can come on.
If you find it is wet in there, drain the plenum, remove and dry the ecu.
Chris

[sworks]

As above check the plennums, the first signs of water ingress can be temp gauge heated rear window and Rev counter not working

[Lovel]

If you have eliminated the potential of flooding in the plenum. The symptoms sound like you may need to replace the ECM. Classic sign of internal failure are no rev counter. Cruise. Heated rear window.temp gauge.

[marinabrian]

CANBUS messages failure Instrument Pack 3.

Unrepairable fault within the DDE4, as a result of the parts being no longer available to repair.

New ECU required, not having much luck with this car Graham :getmecoat:

Brian :D

[grahamw]

Thanks for your helpful replies.
Plenum checked and all clear as usual..
Now lost rev counter too, and trip computer no longer shows mpg.
Having just replaced the ecu, I hope that isn't the problem..

[grahamw]

Thanks MarinaBrian,
Well, just in case something like this happened, I kept my old ECU,immobiliser and key chip so I'll fit them now and see what happens.

[grahamw]

Perfect diagnosis, everything works perfectly with my old ecu fitted.Thanks again MarinaBrian
Re:
New ECU required, not having much luck with this car Graham :getmecoat:
HAha, I've never had so much luck with one car; all the wrong kind.
Graham.

[marinabrian]

Does that mean you're running an NNN500340 in your car again?

Big Russ will be able to sort you a replacement NNN100692 I'm sure ;)

Brian :D

[grahamw]

Hi MarinaBrian,
That original one is probably winging it's way to you through Russ as 'parts only' :-)
The Immobiliser, key chip and ECU I'm using now I picked up from a running scrapped car. Tried to buy the whole car but I was too late, they'd taken off the wheels, drained all fluids and exploded all the air bags.
Graham

[BigRuss]

Hi Graham, will give you call tomorrow will sort that out for you again, need to do that airbag config too ;)

Russ

[grahamw]

Many thanks for your help Russ, much appreciated.
The CDT is running fine (Actually VERY well with MPG mid forties!) on the old ECU for now. Looking forward to retrieving the 160 bhp ECU when we can.
grahamw

[grahamw]

Hello All,
Russ has reprogrammed my existing ecu, back up to the 160 bhp remap. On a long run ( To pick some union wheels up!) It's sitting at 45 mpg. Still running a bit cool, so once I replace the thermostat, I might find a few more MPG.
Coming through the Yorkshire Dales, I noticed the clutch has started to slip. Oh joy of joys! Should I do it myself, or let a forum expert tackle the job?
Your opinions are valued...
grahamw.

[marinabrian]

Hello All,
Russ has reprogrammed my existing ecu, back up to the 160 bhp remap. On a long run ( To pick some union wheels up!) It's sitting at 45 mpg. Still running a bit cool, so once I replace the thermostat, I might find a few more MPG.
Coming through the Yorkshire Dales, I noticed the clutch has started to slip. Oh joy of joys! Should I do it myself, or let a forum expert tackle the job?
Your opinions are valued...
grahamw.

Do it yourself Graham, lots of job satisfaction guaranteed ;)


Brian :D

[grahamw]

Agreed,
Decided to temporarily give my V6 to my wife :-( So I'll be Ford Transit bound for as long as it takes!)
I need to clear lots of Garage space, then slowly dismantle her diesel in order to sort the clutch.
Parts will not be ordered until I've dismantled it. The clutch does work perfectly, it just slips under hard acceleration occasionally now it's at 160 bhp (Thanks Big Russ:-).
I trust my own judgement, the only thing I'm good at is being a mechanic. So I'm going to carefully dismantle and measure, then replace any components that are worn, but nothing else.
It'll be interesting to see what I find. I've read so many stories about clutch problems. In all honesty, the 'replace everything' comments frustrate me, and suggest a lack of understanding, why not measure everything, check tolerances and confirm how much life each component has left, then once you understand; Make an informed decision as to what needs replacing. Too many components are replaced and even scrapped with 100% safe million plus fatigue life miles left, hence the thriving reconditioning market in clutch and suspension components.
It's not rocket science.
Graham

[SD1too]

I'm going to carefully dismantle and measure, then replace any components that are worn, but nothing else.
... the 'replace everything' comments frustrate me, and suggest a lack of understanding, why not measure everything, check tolerances and confirm how much life each component has left, then once you understand; Make an informed decision as to what needs replacing.
:wot: :iagree: :bowdown:

I don't have a clutch, but as a general repair principle that's always been my philosophy too. Of course it's only possible if you are able to take your time with the job. Two major disadvantages with the 'replace everything' approach are expense and that you never find out why the failure occurred.

Simon

[grahamw]

Nice to find an owner with a similar view of mechanics, quite rare these days.
My wife is very happy to use my V6 auto because; The heater is much better than the diesel, and I'm paying for the petrol :-)
I'll post images during the clutch job in the hope it might help someone save one more 75 from 'The ultimate sin'
Graham.

[grahamw]

Russ has programmed my ECU to 160 bhp, and also a second one as a spare :-)
As a thank you, I've given him all my spare keys :-)
This is a wonderful forum, everyone I have spoken to just wants to extend the life of real Rovers. Can't ask for any more than that!
Graham.

[graham clarke]

Thanks for your helpful replies.
Plenum checked and all clear as usual..
Now lost rev counter too, and trip computer no longer shows mpg.
Having just replaced the ecu, I hope that isn't the problem..

I had these problems when the local garage replaced the thermostat and housing. Ref to the 'testbook' revealed this to be a 'CAN-BUS' problem, but the garage wanted to see it as unrelated to their repair and proposed to look for circuit breaks in the cooling fan control box and behind the dash!
I remedied the problem simply by following the in car self diagnostic tests set out by T Cut (thanks TC), this simple process had the effect of restoring the contact between the ECU and its sensors and everything works again.
(temp and rev and rear screen, and the cooling fan no longer cuts in at start up).

[DMGRS]

I had the same problem, which was fixed by a battery reset. The problem never came back, thankfully. :)

To the original poster, if you're in need of a Clutch Kit I do have plenty in stock - they're here:
75/ZT CDTi Clutch Kit - B&B and LUK (http://www.dmgrs.co.uk/collections/clutch-transmission-parts/products/borg-beck-oem-rover-75-cdti-mg-zt-cdti-clutch-kit-with-slave-3pc-rp1069-uub105301)

Interestingly enough, the ECU in the car I refer to did have liquid damage - but this manifested itself many months later. Perhaps they could have been related.

[SD1too]

... and the cooling fan no longer cuts in at start up).
:welcome: to the forum Graham.

Just to clarify, if your air conditioning is in 'Auto' mode, or the windscreen demist button has been pressed, the radiator fan should run continuously as soon as the engine is started from cold. If it doesn't, please report back for a remedy.

Simon