I didn't find this one in previous threads. My XK8 has always started and run without any issues at all, has always run perfectly for 3 years I owned it, now has 40k miles. Driving routinely at 35mph last week it suddenly stopped responding to throttle. Was able to pull off and get parked ok but then would not restart. Cranks enthusiastically but doesn't fire.

Had it towed to local garage. Their OBD reader reads several confusing codes including something about the security system. My OBD reader just said P1000.

They haven't started troubleshooting yet, anybody have any ideas?

 

Hi sls,
Ask the garage for the codes they pulled - the raw codes, not any interpretation of them - and post them here.
Could be fuel pump, electrical or a host of other things and the codes may help the diagnosis.


As it's a 2001, then you *need* to know the state of the chain tensioners. Even with the low mileage, plastic secondary tensioners are, as a member here so eloquently put it, 'grenades with the pins pulled out' on a vehicle of this age.

 

sls-101,

After 3 years driving you've a P1000 - which basically means that all the car monitors haven't done the full cycle of diagnostics - Weird! Unless the garage cleared the DTC codes....

On the XK8, my first suggestion is always to check the battery and their cables & connections. Low voltage causes all sorts of weird DTC messages. Maybe your alternator is going, causing the problem. I know you said it cranks, but low powered batteries are known to crank the car, but there's not enough to power the car systems also.

 

I will second what michealh states regarding tensioners - as one who suffered said grenade catastrophe while driving - symptoms similar to yours. Hopefully yours did not suffer the same fate but it can be rebuilt.

Here's the direct link t o my thread with pics
https://www.jaguarforums.com/forum/x...0/#post1849908

 

Thanks for comments guys.

After clearing OBD codes the following recurred:
U1135
U1041
B1595
B2334

Regarding the ticking bomb, I defused that in 2017- new tensioners primary & secondary, new timing chains etc. Also the short heater hose.

SLS

 

I take it you ruled out the obvious failure of a fuel pump?

 

It's also worth working through the no-start troubleshooting from member Gus' site here:
JagRepair.com - Jaguar Repair Information Resource

I had a quick scoot through your history but didn't spot anything tensioner-related, although it is entirely possible I missed it.

A quick search on those codes indicates that they might be spurious depending on code reader type and/or battery state.

 

The codes won't be confusing to anyone with the relevant Jaguar DTC lookup for your MY. Post the codes or "troubleshooting" remains "speculation and guesswork".

Graham

 

Troubleshooting a no - start is neither speculative nor guesswork.

First, has a code been thrown that clearly points to the problem, such as CPS. If not, then rule out the obvious. 'Do I have fuel pressure at the rail and do I have spark.'

If both are present and you continue to have a no - start, then the deeper dive becomes necessary.

 

Codes are from the 2003 MY docs, so YMMV. It looks like multiple modules can complain with the same code, so you might have to find out which one did. The immediate concern is the ignition switch, but I don't believe it is a common problem. Instead, it looks like the SCP network is not operating, which prevents the car from authenticating the crypto chip in the key. I would focus on the SLCM and BPM. The letter/number references specific spots on the harness and are documented in the electrical guide. You also need to check the TSBs on jagrepair.com related to the instrument cluster and bad soldering, which is apparently easily fixable with basic soldering skills.









Best of luck, keep us posted.

 

Once again thanks to all contributors for your valuable comments. It appears the fuel pump is bad, new one on the way. However the ignition switch / key security validation issue as fmertz described is probably the next challenge. Could this have been caused by the towing and fiddling subsequent to the initial problem?

Once we have fuel pressure we'll see where we're at, but my expectations are low. According to a local indie shop the security validation is a common Jag problem that probably requires dealer attention. But first I might have them run thru the steps fmertz suggests.

Will update when I have more news.

 

Ok guys sorry for MAAN (Much Ado About Nothing). The fuel pump was the problem as mhminnich tried to tell me. All the other error codes were just noise (?). It seems we needed less technical analysis and more horse sense...

SLS

 

Haha. Glad you got it figured out. Now I can tell my wife that even a horse's *ss occasionally gets it right.