Car wont start, although it did start 4 times on the trot and drove fine but then nothing.
I had no codes, so I checked fuel pressure, changed the crankshaft sensor and the spark plugs. I then got a P1229 code, so today I replaced the throttle body. I have no codes anymore but it is still in failsafe engine mode. Also put a teaspoon of oil down the barrels in case it had bore wash.
My question is ladies and gentlemen... should I now be looking at the ECU?
I thank you lol

 

Is it starting now or still no start?


Any other symptoms? Do you have fuel pressure, spark?


Any other codes logged?

 

I have fuel pressure I don't have spark when engine failsafe mode comes up but it will randomly disappear and the car will start but as I said, it has come back now and no start :-(
No codes now either

 

Interesting


A tech I used to work next to had a similar issue. It was running when it came in, just for a service, then after it wouldn't start. Turned out the issue was inside the ECU, problem on ignition circuits.


I don't know about UK - but I would assume there is someone there who repairs ECU's. It's just a matter of taking it out and finding someone who can have a look.


Someone from UK here might be able to chime in - worth having it checked.

 

Have you checked all the loom connections and battery voltage? Should be a minimum of 12.6 volts across the terminals with the ignition in the OFF position for ten minutes.

 

 

Its turning over on the battery but not starting?

I've got a failsafe warning when my alternator died and I ran on the battery for 17 miles around the time the dash gage said 9 volts (but who knows how much voltage the battery actually had).

 

Could it be bore wash?

If it spins but doesn't start then... maybe.

 

It's not bore wash, as I said in my first post I oiled the barrels. It will randomly start and run completely normaly even if the engine failsafe pops up on the dash but if i turn it off with the engine failsafeon the dash it will not start again. The RAC guy put a new battery on it and it still wouldn't start. I also have a new battery on it now.
I checked all the loom conections, everything is clean. I'm thinking ECU?

 

Code P1229 possible causes are:

1. Throttle motor disconnected
2. Throttle motor to ECM drive circuits short circuit or open circuit
3. Throttle motor failure

You've gone direct to (3) which should therefore also have eliminated (1). ECM faults are rare - harness and connector faults are much more common.

Still being in failsafe mode must have associated code(s) .....

Graham

 

I checked the wiring,everything is clean. Unbolted the main conector behind the throttle, everything is clean and shiny in there too. I (unfortunately) no longer have any codes.
IO guess it can't do any harm having a look at the ecu?

 

JagV8 mentioned bore wash. It wouldn't take a lot of work to pull the plugs and do a compression check.

 

He says he did. However by now it may be like that and it's worth looking (again).

If codes were cleared then also all the OBD monitors were cleared. Any that have not yet set again may be causing the car to be unable to flag codes. And also unable to set the monitor(s) - Catch-22.

(It's why clearing codes is not really a good idea.)

 

Have you checked the operation of the throttle body? If you pull the intake tube and put the ignition on (engine off), you should be able to see the butterfly move as you press the gas pedal.

From memory, there is a throttle body programming procedure. I have not had to deal with this, so I am unsure. You can always do the basic procedure: ignition on, engine off, slowly press the gas pedal through it's entire range, including the kickdown switch if you have one, then back off. Do this a few times to "teach" the ECU about the range of the pedal sensor. Free procedure, nothing to lose.

The proper path is to try and locate a Jaguar-aware scan tool and see if there is anything stored. For no-start conditions, I believe the ECU stores live data that can be read with OBD software.

Best of luck, keep us posted.

 

 

Given the age of the car and the things you have already tried, I think it would be sensible to have a look at the ECU to check for blown capacitors. First though you might want to do what fmertz has suggested and see if you can read any live data that might give you a clue when it is failing to start.

 

Turn the key on for 10 to 20 seconds then attempt to start the car do it in “P” & “N” and see what takes place.

 

 

I am not sure at the moment because I am experiencing the same issue. I am at the point that I feel it is the ECM but want to do additional testing. With my situation I could turn the key on for about 20 seconds and then start it and it would start. The attached video will show you how I am not getting spark on the start action but after a few seconds on the second start it starts up.

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