What does failsafe engine mode mean on a 2000 S Type Jaguar?

Engine fail safe appears when there is a hard fault code, usually tranmission problems. the computer reduces engine power to have the least amount of strain on the vehicle until you can get to the shop.

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2000 Jaguar S Type 3.0 V6

Unplug two sensors attached to where the hose going to where air filter is, unbolt 4x long screws around the throttle (keep an eye on the gasket between the engine and the throttle body).

There's two small hoses attached to the throttle, if you can't remove them off (really tight as) no need to worry because you can start spraying the Throttle Cleaner (leave it for a while) to the throttle, I suggest you get a box of tissue, before you start wiping the throttle (clothes not good because it will smudge the oil all over the inside throttle), spray a little to the tissue before wiping it, keep doing it until you see the inner body is light silver color.

Then you can start cleaning the butterfly inside with tissue sprayed with spray cleaner, use your thumb to hold the butterfly piece (not with any sharp tool) while your other hand/fingers cleaning it.

Before you put it all back, it's not a bad idea if you start cleaning the air filter box where your air filter seating (or replace the if it's old air filter), spray with an Electronic Spray Cleaner each and every sensors and the connectors you unplug.

I wish I could have video what I did and post it here or on YouTube.

I get this idea from jagforum, following a trends in the discussions. I thought I share it with others, after doing this procedures to my Jag, I will update this article if there's improvement or the warning will go away. . . . .