I want you to see the culprit to several console error messages. Hey! Not saying this is exactly your problem or your fix but this was mine for the following. Fix: Replace brake light switch.

Failsafe engine mode
Reduce Performance
Cruise control not working
Chk Eng
Gear Fault
Engine not starting sometimes

This is the module I replaced. You can see that is not totally closed.


206-07AM3.pdf

 

I keep waiting for something to pop up because it was happening often... especially no start with turning the key and failsafe mode msg. This is not the case! No messages, car starts every time, cruise engages each time.

I hate to think that many of you are spending so much time looking elsewhere for the problem.

Installing the brake light switch was painful because it was so hard to get to and then attempt to use both hands. I struggled to find wrench small enough and then hold the nut while twisting the bolt. I'd have to take breaks. Maybe I need to lose some weight. I used my iphone as my light source with the built in flashlight... a godsend!

I felt I was taking a chance getting a used part but I could not see spending $134 for a new one and it end up not being the fix that I needed. As soon as pulled the bad part and compared, it was obvious it was broken.

 

I just did a 1000 mile weekend round trip and had no problems whatsoever... well I did have to replace the battery but that had nothing to do with brake light switch.

I'm relieved to not have any dash messages for the first time in a long time.

 

Yes, I have seen this before but don't just want to change parts it has to be a faulty something, haha


Thanks again

 

Hi Morpheus,
I have had these symptoms occasionally, over the past week. I also get a code 1111, 1646 and 1647. Did you get any codes like this, or am I chasing something else. My failsafe mode kicks in randomly, can be at the end of a drive, just after starting, at a roundabout, and today when first starting the car.
I will try to remove it tomorrow and clean the contacts, see if that makes a difference.

 

P1111 is not a code. It indicates ECU check of systems complete. Assuming the other two are also P, they indicate the upstream oxygen sensors are malfunctioning.

 

Thanks RJ,
I went back to my OBD2 reader ad realised that was an old set of codes, and all I am getting this week is the 1111 code, nothing else.
The car is now stalling when I come off idle, so I need to look at everything; not sure why I don't have more codes...ideas anyone?

BTW, I do know I have a broken part load breather which is just taped up for now, until I source/fit a new one.

 

I am not familiar with an XJ8 Sport sold in the UK: Supercharged? If so, try swapping the fuel pump relays; if not, try swapping one of the other relays with the fuel pump relay and see if that fixes the problem.

 

That sounds more like a throttle body issue. You might start with cleaning the throar and butterfly with a rag dipped in carb cleaner. The disconnect the plugs on the throttle body and use contact cleaner on them. Disconnect the battery first.

Your symptoms are not really similar, so you might want to star a new thread if this does not solve the problem

 

I just removed my brake switch today as a culprit for not allowing gear lever out of park position
Upon inspection I found the micro switches to be fine
However the ratchet piece which activates the micro switches is very stiff and as a result was not following the break pedal when pressed thus not opening the micro switches
I took the micro switches out of their housing and reconnected the switch to its harness and straight away solenoid was activated to allow gear lever to move out of park position