Code P1111, Car Will Not Start

[Tattyhead]

Hello Members

Re: 2002 XJ8

Car has been running fine, this morning I went to start it and it flatly refused to start.
Engine cranks over fine. MIL light displayed and I was able to retrieve the code P1111. No other codes stored.
I have read that this is a 'System Check Ok' code with no fault but could also be 'Intake Air Temperature Sensor Circuit Intermittent High Voltage', which is a bit confusing.
The dash displays, Trac Not Available and ASC Not Available.
I can hear a buzzing where the black aluminium right angle elbow of the air intake meets the throttle body.
If anyone is able to help I would be very grateful.
Thank you.

[andypryce]

If it’s turning over but not firing I would suspect crankshaft position sensor, a fairly common failing

[Tattyhead]

Andy thank you.

[Andy P]

Hi Tattyhead,
Sorry to hear your having problems.
Code P1111 relates to the Systems Readiness Check which when completed shows P1111 and is not a problem code.
While the test is being conducted the car will show P1000 which is not a problem code either.

One of the first things I would check would be the fuel pressure to determine if the fuel pump has failed.They can go without any warning.
Not the best time of year to fiddling around under the bonnet I know.
You could try cleaning the MAF sensor,easy to do.
Might be worth doing a hard reset,also easy to do.
Is the buzzing from the throttle body continuous or only when you first turn the ignition on?
Sorry I can't be more helpful but good luck and hope you get it sorted.
Take care.
Andy

[Tattyhead]

Hi Andy
Thank you for your reply.
Yes not the best of weather for working under a bonnet.
I’ll give the MAF a clean in the next couple of days.
If no joy when it’s a bit warmer I’ll check fuel pump. Would the pump failure not generate a fault code?
The buzzing from the throttle body appears to be all the time, well 10 seconds I turned the ignition off.
How do I do a hard reset by the way. I might as well try it.
Thanks again.

[andypryce]

I doubt a fuel pump failure would throw up a fault code on a 2002 car, the OBD system was developing rapidly at that time, my 1998 XK8 is pretty basic but my previous 2006 X150 was much more advanced. I may be wrong, but in the absence of any fault codes I am not sure if a hard reset will help? No harm though, as long as you have the radio code to hand. Cranking without any sign of firing does sound to me more like a sensor issue such as camshaft sensor, though again that may throw up a code, so I could be off the mark.

[Tattyhead]

Andy
Thank you for your advice, still too cold to tackle it.🥶 Changing the fuel pump looks a pain, let’s hope it’s something easy.
Mark

[andypryce]

Agree definitely too cold, make it think you are sulking, perhaps it will fix itself
One other thought, fuel pump fuse, though why on earth that should blow who knows. Easy check though.

[Andy P]

How do I do a hard reset by the way. I might as well try it.
Thanks again.

Hi Mark,
Here is info on doing a Hard Re-Set:
Make Sure You Have Your Radio Code

Hard Re-Set

Once you have disconnected the negative terminal you have effectively broken the circuit so no risk of electric shock.
Here's a bit more info to clarify:
You have to have a COMPLETE circuit for power to flow. If the negative(or pos) is unhooked from the battery you can touch the DISCONNECTED negative to the STILL CONNECTED(or visa/versa) Positive. There is not a complete circuit and no power flows. you can disconnect both if you feel more comfortable, but its not necessary, it just takes more time. The reason I and others say disc the negative is 2 reasons
1) it is usually the closest and easiest to access.
2) there is usually little or nothing else attached to it.
The reason it works on the capacitors is THEY still have a complete circuit on the car so you are giving their positive terminal a path to ground to discharge them. And since the ignition provides a mechanical link to circuits that are isolated. You can/should also switch the key to the on position while the battery is unhooked and hard reboot again. Then shut off the key and go back and reconnect the battery.
Hope you get it sorted
Take care.
Andy

[Tattyhead]

Many thanks for your help Andy.

[Dave Eynon]

Hi, I have followed the thread and thought I would offer another potential cause of the failure to start. In the absence of any fault or component failure it could be that the engine has been flooded with petrol, and now with soaking wet (in petrol) spark plugs it will not start. This has happened to me with an X300 and my XK8 in the past. There is a procedure to purge the engine of the excess fuel if no other reason is found after checking.

[Tattyhead]

Hi
Thanks for your reply.
I do remember an earlier XJ8 flooding after I shut the engine off too soon.
If memory serves me correct I pulled the spark plugs and fuel pump fuse and cranked it over till it cleared the cylinders.
It’s still too damn cold to work on it🥶

[andypryce]

Yes you just need to pull the fuel pump fuse and crank it for a while, no need to remove spark plugs

[Tattyhead]

Thank you.