FAIL SAFE ENGINE MODE

Connect it to a professional grade scan tool computer.

Sometimes the engine failsafe mode is triggered due to a sensor failure or an electrical glitch. It's also common for a security system fault to engage this warning light, which means it's not always a mechanical issue that's causing the failsafe.
Oct 31, 2018

What is the Engine Failsafe Mode? ' YourMechanic Advice

https://www.yourmechanic.com > article > what-is-an-engi...

Vehicle Engine Failsafe Mode Explained and How to Reset it

https://scanneranswers.com > Repair
In most cases, the check engine light will turn ON as the engine switches to failsafe mode. But having a check engine light does not ...
Jan 26, 2021 · Uploaded by robinsonsauto
‎What is the engine failsafe... · ‎Fail-Safe mode isn't always...

great question, but engine failsafe or transmission?>
no year stated, and is very key to answers,
the PCM runs the engine, and if any sensor fails.
the PCM Sees that (called catastrophic monitors) and instead of
dying like a race car does (like this) the factory PCM is smarter than the average bear.
it MIMIC's the dead sensor from about 1985 to now. most cars, in USA. called OBD . "simulates it"
the ECu then logs ERRORS called DTCs ,you scan the PCM(or ECU) and it shows, say , dead CMP (crank sensor) "wild guess"

one example is a dead MAF, (or MAP) the simulation is very very crude, and engine will misfire and foul spark plugs with carbon.
this is very common, and worse prior to 1996 , in USA.

so the CEL lamp glow running, that means Scan ME.

Not starting is another matter,
good compression on all cylinders
good spark on all spark plugs, (not black tips (look)
good fueling, of the above 2 are good, all cars run with test fuel now for about 3 seconds, long each spray.

the fuel tank can be missing and i can keep the engine running for 5 minutes or longer, with my bottle of spray fuel.
proving , you have fueling problem
(low fuel pressure or too much)
ill not do fueling as that is 3 pages long "injector tests"

Hi, fail safe engine mode means that the ECM (Electronic control module) or computer box as some know it, is running in a mode whereby it is bypassing a particular component in the engine that has gone faulty in order to keep the car from cutting out, or has picked up an erratic function in any component, which is more than likely an electrical problem and could be one of the following which have to be checked by computer analysis equipment at the Jaguar agents or any one else that is familiar with the process that is required to trace the fault. Here are the possible causes: 1.Erratic wire connection 2, Engine cooling Fan thermal switch. 3. Control module 4. CKP sensor 5. Computer box not functioning correctly (a rare fault) 6.Engine coolant fan not working, or running erratically. Unfortunately only a computer analyis will depict the location of the fault and if the repair man is very experienced will be able to sort it out quickly with the computer analysis.( Although I strongly suspect it to be the cooling fan thermal switch which is working erratically and will soon fail completely.)
So get your car to the experts as soon as possible especially if it could be the cooling fan thermal switch, which could cost you a major expensive engine repair job if your Jaguar overheats.
Have a good day.

check for spark at the plug lead while cranking engine

Yes. No crank sensor signal usually means no spark. The ecu has to receive crank position to set spark timing. I think you've really hit a big problem. You may need to get in touch with some people who have done this mod. I've always heard it's best and easiest to swap the engine with its ecu and the wiring harness into another car. Or something more compatible with that jdm engine.

is the transmission slipping?electronic controlled transmissions go into fail safe mode starting out in a higher gear

change the pedal sensor...thrttle is fine and will function properly as soon as its changed..make sure once you change it you turn the key to position two for 5 seconds then turn it back to position one ,then wait ten more seconds and turn the key to postion two for 5 seconds again to allow the ecu to calibrate.And make sure you unplug the neg terminal to do the install...once reconnected follow the above procedure...the crank the car.

There is no simple answer, there are to many variables. If you have access to a scan tool, pulling the codes should help. Without them its back to old school hunt and peck method. At this point we need to narrow down the problem. You need to test for spark.

1. Tag and disconnect the spark plug wires from the spark plugs.
   
2. Remove the spark plugs and install the spark plug wires to each spark plug.
   
3. Ground (do not hold spark plug) the spark plug; check if spark occurs while engine is being cranked.
   

Crank the engine for no more than 2 seconds at a time to prevent flooding the engine with gasoline.
If you have spark, You will want to make sure you have fuel injector pulse, along with fuel pressure. If you have spark ..simply spray some starting fluid in through the air filter and hold the gas pedal to the floor and crank it over while spraying. If it fires up, you know it is fuel related( fuel pump, regulator, or ECM if no injector pulse) . If you have no spark then look at ignition coil connection and trace through to the distributor( if equipped ). The crank shaft sensor has a tendency to fail on these as well. This should give you a few things to test and check to start you on your way to narrowing it down. If you have no spark then look at ignition coil connection for power and trace through to the distributor( if equipped ). If it is DIS( no distributor). It may be the Crank sensor or the ECU. The crank shaft sensor has a tendency to fail on these as well.
The ECU uses the signal sent from the Crank sensor to trigger the spark and fuel injectors. ( make certain you have checked all fuses)

I do not know about a Jag. But the "fail safe engine mode " on my GMC means the Engine Controll Computer has quit working.

My Son's 01 Sonata displayed the exact same systems and it was his catalytic converter. The metallic sounds were the converter guts disintegrating.