Bentley Turbo R

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Discussion

Peter Baverstock

Original Poster:

6 posts

129 months

Wednesday 24th July 2013
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I have a Bentley Turbo R 1997 model that I believe has traction control. The warning light on the information panel tells me there is a 'trac fault' Any idease what this may be and how it can be rectified.
When the car turns a tight circle there is a definate scrubbing of rear tyres.
Pete

Chromed

91 posts

133 months

Thursday 25th July 2013
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I don't have experience of your car, but the first thing I would check are the sensors, probably on the rear wheels that the ecu will use to monitor wheel slip for the traction control. Good luck.

PaulKemp

979 posts

145 months

Friday 26th July 2013
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Often traction control is used to replace a limited slip diff, if you rear tyres are scrubbing then one side is getting brake pressure
Check OVD codes
Check sensor rings
Swap sensor on rear wherls

Peter Baverstock

Original Poster:

6 posts

129 months

Friday 26th July 2013
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Thanks Paul, I understand that, however the indicator on the information panel tells me there is a track fault and the track button on the console does not appear to do anything. I am therefore coming to the conlusion that it is some form of electrical fault, switch, relay, solenoid or similar. What do you think?
Peter.

TheEnd

15,370 posts

188 months

Friday 26th July 2013
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I'd assume there is an ABS light that comes on when starting, but turns off?

If that happens, the wheel sensors are most likely OK, and the problem may lie at the engine side, especially if it has a secondary electronic throttle to limit power to cut wheelspin.

amtrac

3 posts

165 months

Tuesday 12th November 2013
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Peter did you ever find out what the Trac fault was ?
I have the same prob on a 21K mile RT, and must now delve into it, because it is being prepared to be sold.
Since the sign is on as soon as the ign, I assume it is not the wheel sensors of the phonic wheels.
They haven't moved yet.
I've also tested them and get similar resistance fluctuation when each wheel is turned.
JCT 600 explained that the ECU on these is old enough not to have a logging memory, so as soon as the fault is corrected, the sign should dissapear.
So it's not a residual sign, it's a live fault when the ign is turned on.
They also plugged an ancient fault tester into the system and said he suspected the front right Abs sensor, but I pointed out the above, and that the ABS yellow warning wasn't on and it also that the ABS seemed to be working.
He agreed, and gave up.
It's been like this for some years, and passed it's MOT each time with the fault.
I've long suspected the centre consol switch and circuit or the power limit relay - front left of the engine bay, but could find nothing wrong with the components.
Did you have any luck ?
Another (RL in Mulberry) at Catterick had the same prob, so it seems a common one. (he sold his to get rid of the prob.)

fatjon

2,175 posts

213 months

Tuesday 12th November 2013
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Battery and alternator worth a check. On Jaguars the ABS system checks battery voltage before and after start. If it outside tolerance and the ABS electronics cannot be trusted to work reliably it aserts an ABS fault and stops the system working. Logic is that in an engine stall situation, without the alternator, a battery in a questionable state might fail to work the ABS ECU and ABS pump correctly and leave you with no effective ABS. Better to put up the light and disable it at start up than in an emergency braking situation.

Check that the battery is holding a steady 12V with the engine off, not dipping below 9V during cranking and hovering around 14.5v ish when idling.


fatjon

2,175 posts

213 months

Tuesday 12th November 2013
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And yes, I know it's not a jaguar before anyone points that out.

TheEnd

15,370 posts

188 months

Tuesday 12th November 2013
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Is this the BMW 4.4 engine with a turbo on it?
If it is saying just Trac (which I assume is traction control) but no ABS lights, it could be the secondary traction control throttle, which means all of the ABS system will be working as normal, but it isn't able to close the secondary electric throttle to cut power if needed.

amtrac

3 posts

165 months

Monday 18th November 2013
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Thank you both
It's unlikely to be the battery, because it's been like this for some years, and there have been various new batteries due to lack of use.
the alternator is fine.
The engine is the 6.75 Bentley Turbo, but it does have an electric power limiting circuit (throttle) which I've had probs with before.
The relay is which cuts the power is front left of the engine compartment.
Might look there again.
In this case it is the opposite to the original lack of power caused by this relay.
I rather think it gets full power but no traction control power limiting, and the on / off button does nothing.
If it wasn't for the irritatling sign, who would care.
Still wondering what Peter Bavistock found out about his.
On the few occasions when I used this car, one of the delights was going on to the A1 dual carriageway nearby.
Prepare by selecting 1st and Sport, and disable the traction control.
Make sure you're in a straight line before giving her the beans.
Nice people can be seen in the side mirror, pulling out to make room for this old lady.
That's as near as they get.
The bonnet rises, there's a rumble from Australia, and the rear view turns to blue smoke, which was your back tyres liquifying.
Notch it to second at 4500 rpm, and pull out of the slip lane doing a nice round undisclosed figure.
Notch it into Drive, and settle back to the traffic speed.
Costly, but immensely satisfying.
They are also the ultimate 'drifting' car on a race track day.
One hand and one foot job.
Real easy.
In the 1980s I used to spend a lot of time at Hethell on the Lotus test track. (Esprits - lots and L ots O f T rouble U sually S erious).
In about 1986 on Tomorrow's World, there was a bit about Lotus fitting a new concept - Active Ride - to an Esprit.
Footage of a green one (with) and a yellow one (without) going round the track to compare the tilt angles.
In 1988 Bentley fitted it to the Turbo R without bothering to tell the clients.
They probably wouldn't have understood it.
Brilliant bunch.


amtrac

3 posts

165 months

Monday 25th November 2013
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The more I look at this, the more I think that 'The End' might be on to something.
The electronic limiter throttle is disabled for some reason.
The ABS is fine, and the trottle isn't being cut when the back wheels spin.
We tried it, and the two black marks are still on the concrete.
This may be a Bosch system ? Like the BMW, so if you have previous experience of where to look on this system, it would be appreciated.

TheEnd

15,370 posts

188 months

Monday 25th November 2013
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It would make sense.

I know of similar things with BMWs if they have a strut brace fitted as sometimes the engine will cant over and it'll knock the ASC throttle plug out.
The ABS carries on as intended, but it can't limit the power like before so only the traction light comes on.

When an ABS sensor goes, both traction and ABS comes on.

Without getting fault codes, it's hard to say, but the most likely component to go is the electronic motor for the secondary throttle, but you won't be tripping over them in a breakers yard.

Peter Baverstock

Original Poster:

6 posts

129 months

Tuesday 26th November 2013
quotequote all
I have got no further with this, however if it were the throttle limiting system, would the system know this is affecting the traction control and therefore post the warning on the dash at all times, would this not simply appear when traction control was required. I also believe it is more than traction control, as mentioned in my initial posting it appears to be limited slip in that the diff is partially locked, is it not more likely to be a switch, solenoid or relay problem?
As previously mentioned this is the 6.75 litre engine.

TheEnd

15,370 posts

188 months

Tuesday 26th November 2013
quotequote all
On the BMW's, there is an electrical self test to make sure everything is plugged in when you switch the ignition on, but it won't know if it works until it tries to move something.
If there are other parts to do with the diff, then that does add an extra layer.

Peter Baverstock

Original Poster:

6 posts

129 months

Sunday 10th August 2014
quotequote all
Thanks Guys, I have not resolved the traction control problem. I am more than ever convinced the car is fitted with a diff lock or similar, when turning tightly yo can tell one or other rear wheel is scrubbing. When the car is jacked up and in park you cannot turn either rear wheel, if the diff were not locked one wheel would be free at all times.
I also do not think it is the swith, if it were it would simply tell me the diff was locked, but the fact that it tells me there is a track fault means it knows something is not working correctly.
HELP

dingg

3,983 posts

219 months

Monday 11th August 2014
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try rotating the wheels when in Neutral

P locks the box

bentaylor1

2 posts

83 months

Tuesday 30th May 2017
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Hello: If I can join this thread with a similar problem: I have a Bentley Turbo RT 1997 - 36k miles and in very good condition. However I have had similar problems for the last 18 months. I moved my car to Hong Kong (from the UK) and shortly afterwards a TRAC FAULT intermittently would appear on the console and ALL POWER was lost - typically at low speeds and within 5 minutes of starting the car but can be quite dangerous with the car being idle in the middle of the road. Typically all I need to do is turn the ignition off once or twice and it will re-set itself. Another fault has also appeared normally after the TRAC FAULT appears and reads CHECK GEARBOX. I imagine this is associated with complete electrical failure from the TRAC FAULT and the car stalling and idling in "D". I haven't changed the speed sensors yet but thought it might also be an ECU or another electrical fault as other faults have appeared including AUTO RIDE, the rev counter flipping erratically and the Battery and petrol garage backlights recently ceasing to work - Sadly my local Bentley specialist doesn't seem to know what's going on other than suggesting to change the speed sensors (at a cost of around GBP2,000) if anyone can shed any light I will be forever indebted.

loel

3 posts

66 months

Friday 26th October 2018
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My 1997 Bentley Turbo RL has 68,000 miles. I have been unable to use it for the past two years (except for trips to mechanics) because of almost exactly the same behavior described by bentaylor1. I am optimistic that I might now find out how to fix it!
The engine stops without warning, with a console display that reads TRAC FAULT alternating with a red display of a battery and oil can, and sometimes with a CHECK GEARBOX display. So far, the engine has stopped at low speeds and with a place to pull off the road. The engine also always stops if the car is started and parked with the engine running in neutral for about five minutes. Whether the engine stops while the car is parked or under way, it cannot be re-started until a few minutes have elapsed. Battery, oil levels, solenoids and fuses are OK, but without a manual I'm not confident that everything has been checked.
I live about 300 miles from the nearest RR-Bentley dealer, and have not been able to figure out the problem with help from local shops. Any ideas or suggestions will be much appreciated.


Edited by loel on Saturday 27th October 18:04

bentaylor1

2 posts

83 months

Monday 26th November 2018
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Gentlemen

I eventually (after 2 years) managed to fix my TRAC FAULT issue - the problem was the alarm/immobiliser (the Ecu) - although I live in Hong Kong I had a new one built by John Bowling johnrr@btconnect.com. Tel: 01204862500 and shipped to me for fitting locally. That was a year ago and I have had a faultless car ever since. this guy is an electrical genius (as far as Bentley's go)