Hi all!

I'm a Jaguar novice looking at several XK8s (mostly 1997-2000 purely for aesthetic reasons - and yes, I've read up on Nikasil, water pumps, tensioners, etc.) to find a good one for me.

The current front runner is a 1997 xk8 (4.0L) with 86K. The cruise isn't working.

Every time one tries to set the cruise control, it fails to set (sometimes it will feel like it catches for a moment), the cruise button light on the center console goes out, and an amber light with an "Engine Fault" appears on the odometer screen and stays there.

No check engine light comes on when this happens and I was running a wireless OBD2 reader using Dash Command while it happened last time and did not see any error codes come up.

If you restart the car everything is fine again until you try to engage the cruise.

I am paying a Jaguar dealership to inspect it tomorrow before making an offer. They want an extra $220 to pull codes & diagnose this cruise problem. On top of the $325 I'm already paying them to inspect the car ($175) and diagnose a climate control issue ($150).

From reading through past posts am thinking this is problem is probably (in order of likelihood):

1) a faulty Brake switch (BPP switch)
or
2) a vacuum problem (line or the vacuum thingy on top of the the engine near the rear)

My gut feeling is that it's probably a relatively minor problem, so it's not worth it at this point. Skip the diagnosis, negotiate the price down a little, buy the car, and then do the brake switch myself (leaving the bracket on). Then if that doesn't work take it to an independent Jag mechanic I have picked out and go from there.

But on the other hand I know nothing about XK8s that I didn't read online in the last month or so.

Do you all think it would be worth another $220 on a car I still might not buy to diagnose it?

Are there other probable causes of the amber engine fault only when the cruise fails to engage?

Thanks!!!!

Red

 

Another possibility is a throttle body problem. I often have cruise control problems when I've been driving for a couple of hours, which I suspect are due to the sliding contacts in the guard section. Again, no codes, but no engine fault either.

Unless the problem can be identified upfront you could invest a lot of money later, especially since a dealer will want to put new parts in rather than rebuild/repair. There have been many cases of replacing parts until the problem is fixed, often at a cost exceeding the value of the car.

So either walk away or know exactly what is wrong and how much it will cost. Also, plan on spending quite a lot on repairs and maintenance if you don't do the work yourself.

 

Got the report card back form the local Jaguar vet; it sounds like there are broken vacuum lines so presumably that's what's causing the cruise issue.

 

If that's the case and all other is well, then consider this a good find.
Keep us updated

 

Excellent news!!! It's fixed!

The mechanic's "broken" vacuum line turned out to actually be an unplugged vacuum line rather than a broken one.

I plugged the rear line back into the T-fitting pictured below. Once I did that the cruise control A) worked beautifully & B) did not trigger the amber engine fault code anymore! And there was much rejoicing!

Anthony8858, there are actually are a number of other small issues: The interior trunk lights don't work, the fuel sending unit is bad (ridiculously easy to install on a '97, btw), 1 bulb burned out in the radio face, another bulb out in the climate control panel, slightly bent antenna (works great tho), needs cam cover gaskets (& presumably upper tensioners), both rear HK speakers need to be re-coned or replaced, the auto dim rearview mirror needs to be redone, and it'll need various fluid flushes/changes including the transmission.

Still it looks nearly brand new if you are a few feet away and I am loving it so far. It was about 70(F) here today and I got to drive Mrs. Peel all day with the top down!




View from between the engine beauty cover and the plastic fresh air intake thingy (technical term).



Where I am shining the flashlight is the general location of the vacuum T-fitting the hose slipped off of on the passenger side, near the back of the engine bay



View from sticking iPhone down between the plastic fresh air intake thingy (technical term) and the firewall.

 

p.s. I'm feeling glad that I did not choose to fork over the additional $220 to have the Jaguar dealer mechanic specifically diagnose the cruise control problem...

 

Well done, that man.
Don't forget to check battery voltage first thing in morning after a good run day before or overnight charge . . . 12.6V is good with engine not running.

Cheers,

Ken

 

Red
You are a star! Had the same problem. Amber engine fault and no cruise control. I read your post and checked under the bonnet (hood!) and loh and behold - disconnected pipe!!!
Refitted to T-connection and it works just fine! I wonder how the pipe gets dislodged in the first place - it's a very tight it on the T connection.
Don't you love it when you expect to have to pay out big money to fix a problem only to sort it out yourself for zero cost.
Ah, the wonders of the internet!
Thanks Buddy.

Steve Swift

 

Yeah. When I bought my 1997 XK8 convertible, the passenger window had a lot of wind noise because it wasn't seating properly.
Jag dealer quoted me $350 to fix it. I found out thru this forum that it I remove the puddle light on the door, there is a hole there where you can stick a torx screwdriver in there that is the window adjustment. 10 minutes later, no more wind noise.

Nick

 

Just wanted to add one thing to this thread. The same thing happened to me on a 1998.

Here's my heads up: I was wondering how this hose became disconnected (vacuum hose to throttle body. Manages cruise control speed on our earlier cars) There was a good reason - engine mounts needed replacing. Heavy throttle and the engine movement pulled it right out.

so if it happens, especially more than once, check the engine mounts.

John