Jaguar xj8 v8 probs

[GNM]

Hi there.
My 2001 jaguar xj8 4litre v8 runs well, but has a few issues i am hoping some one could help with.
Firstly, i noticed a few weeks ago that it pinks a lot when climbing slopes in the road.
Secondly, just yesterday, a notice came up on the mileometer area.." failure eng mode" and an orange light. However, the car drives perfectly!

Also, i cant get the heater to switch to cold air. Air con now not working too.

Appreciate any wise help please.

Rgds

Neil

[GreenV8S]

What fault codes recorded?

[GNM]

Hi. Hopefully getting these Monday morning, 16th.

Rgds

Neil

[stevieturbo]

So it pinks a lot...but drives perfectly, and has warning lights ?

Not really a lot to go on. It'll need more than codes read, but that is a starting point. And done by a competent person with good equipment.

[GNM]

Many thanks.

Yes diagnostic unit checking Monday. Only dash info I have just from yesterday, is "FAILURE ENG MODE" and an orange light. Drives still fine though. Pinking going on for some weeks!

Rgds

Neil

[GNM]

Hi all again.

So diagnostic came up with Brake light switch faulty..re the Failsafe Eng Mode sign.

Found that a bit odd as brake light sw, not and engine fail etc?!

No other codes, so still in the dark re pinking! Tried 97 octane fuel instead of 95, but so far, no change.

Also front suspension knocks...Took front shocks off, no difference. , so replaced, then Took link bars off, knock gone.! So these were new links just a few weeks ago. Any ideas please?

Rgds

Neil

[stevieturbo]

GNM said:

Hi all again.

So diagnostic came up with Brake light switch faulty..re the Failsafe Eng Mode sign.

Found that a bit odd as brake light sw, not and engine fail etc?!

No other codes, so still in the dark re pinking! Tried 97 octane fuel instead of 95, but so far, no change.

Also front suspension knocks...Took front shocks off, no difference. , so replaced, then Took link bars off, knock gone.! So these were new links just a few weeks ago. Any ideas please?

Rgds

Neil

ECU's will often want to see a working brake pedal switch.....calling it only a light switch isnt quite the same thing.

As for the knocks....almost all aftermarket parts are ste, some really really ste, some just ste.
Really...if you want things to last, buy OEM where possible. This assumes the parts were fitted correctly by a competent person in the first place.
But it could be drop links, or ARB bushes causing the knocking. So the parts already changed, may not have been the only issues, but it should be fairly obvious feeling the drop links if they are knackered or not

[Oldandslow]

stevieturbo said:

GNM said:

Hi all again.

So diagnostic came up with Brake light switch faulty..re the Failsafe Eng Mode sign.

Found that a bit odd as brake light sw, not and engine fail etc?!

No other codes, so still in the dark re pinking! Tried 97 octane fuel instead of 95, but so far, no change.

Also front suspension knocks...Took front shocks off, no difference. , so replaced, then Took link bars off, knock gone.! So these were new links just a few weeks ago. Any ideas please?

Rgds

Neil

ECU's will often want to see a working brake pedal switch.....calling it only a light switch isnt quite the same thing.

As for the knocks....almost all aftermarket parts are ste, some really really ste, some just ste.
Really...if you want things to last, buy OEM where possible. This assumes the parts were fitted correctly by a competent person in the first place.
But it could be drop links, or ARB bushes causing the knocking. So the parts already changed, may not have been the only issues, but it should be fairly obvious feeling the drop links if they are knackered or not

+1 If new links fitted and still knocking then it's bushes. (with links off the bushes don't carry any load so don't knock)

[GNM]

Many thanks. Yes link arms were from jag suppliers an say made in germany on them.
Yes so will fit new bushes to anti roll bar.
Thks for brake sw info. Fitting new one of those too.
Pinking..no codes, apart from "unknown"code shown. Yes competent mechanic known for years.
Air con still a mystery. In fact when this not working the ordinary hot and cold from heater controls, not very cold. Blows warm air mostly!
Rgds

Neil

[GNM]

Hello. Recently asked about a dashboard message saying "Failsafe Eng Mode". Diagnostics check said brake light sw at fault, plus "unknown code"

Today have replaced switch and "failsafe" gone! Leaving "undocumented code 128H/296"
After road test, re tried diagnostic check, and now shows all clear and no codes. Any ideas of code meaning please?

Also, the engine pinks quite a bit on accelerating up inclines, and a slight vibration coming from underneath, sounding like exhaust maybe. Visually checked, but nothing loose! Any help appreciated. Thanks

Neil

[stevieturbo]

code means nothing without some information as to what is displaying this code.

And this "pinking"....well, this is your interpretation, as we cannot hear this, it would be hard to say that it is actually pinking because it is incredibly unlikely in any car from the last couple of decades....and could easily be an exhaust blowout or similar.

[Don Roque]

These cars often flash up erroneous fault codes when the battery is getting old. My one used to flash up a traction control error on cold starts. A new battery solved that right away. How old is your battery?

[craigjm]

Don Roque said:

These cars often flash up erroneous fault codes when the battery is getting old. My one used to flash up a traction control error on cold starts. A new battery solved that right away. How old is your battery?

This. It could well be low battery voltage.

[GNM]

Hi there.
Had the car since april 219 so dont know batt age.
However, just once it was flat sm weeks ago and no start. Charged it for a few days and been ok since. Checked at battery suppliers and they said batt in liw state, but see how it goes. What u think?

Rgds

Neil

[craigjm]

Based on that I would definitely change the battery

[GNM]

Ah. Many thanks!
Will do.
Rgds
N