Hi All
We are getting problems on our 2004 S Type R.
Not always, but frequently we get an Engine Management/Systems Fault on the display. This then says Parkbrake fault and then cruise not available.
It starts, idles really rough. If you let it run for a few minutes then switch it off and lock the car. Then unlock, the fault goes and all is well. Until it comes back next time.
It can fail while driving, but always at low engine speeds (750-1200 rpm). Pull over, lock and unlock solves it enough to drive again.
We have experienced a slight surging and dead spot low down in the revs while driving. Comes and goes.

Diags show the following:
P2118: 1) Throttle Actuator Control Motor Current Range/Performance
Pending Fault Log
------------------
P2135: Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation

Is this looking like a gunked up or faulty throttle body?

Your thoughts and feedback are appreciated.
Thanks

 

Failing battery most likely.

Probably not the TB or TPS.

Check battery is at least 12.6V (engine off) after standing overnight.

If OK, check fuel trims which could easily cause the surging etc.

 

Well, I have a hunch - I might be wrong, but it's worth checking, because it is an really easy check:
Already, when I read "Engine Management faults" I thought that, and then the other display faults and THEN: "Throttle actuator control motor" problem, which is exactly, what I thought:

https://www.jaguarforums.com/forum/s...nector-288221/

I think you have a simple problem with the throttle motor actuator CONNECTOR. It's nicely hidden under the big rubber air-intake, and thus it's easily been overlooked.
Thus, it's easily forgotten to reconnect it after doing some work in that area, but also: There is apparently a problem with excessive heat in that spot, which causes that connector (plastic) to disintegrate over time and basically become plain dust and disintegrate completely.

Thus my guess is that your either forgot to reconnect that connector, or it disconnected itself (disintegrated), or it may even look fine, but the electrical contact surfaces inside are buggered. My link above explains, how I fixed that problem...

 

You are like me Peter. A wealth of diy knowledge on these cars. Meaning a catch 22. You can share invaluable tips but it also means a lot of wrenching over the years. Keep up the good work

 

Thanks for the tips there guys.
We had these errors a couple of years ago also.
The previous owner had swapped the entire accelerator pedal assembly, but the fault came back. So we swapped it back to original again, luckily he kept that.
Found a TSB that essentially puts a pad of adhesive tape over some holes in the brace that runs over the top between the struts. It is supposed to deflect any water away from the area of the TPS connector.

When it happened again, we initially swapped out the TPS and cleaned the connectors and sealing it with some dielectric grease. Connectors look normal, no heat damage. All seemed ok.

A while later the fault came back.
At that point we swapped the entire throttle body with a second hand one (actually from a low mileage 4.2 XKR).
All has been great for a while again, now the fault is back manifesting as the faults reported here.
Battery is kept charged and was also previously swapped out for new.

I will go look at the connector again and review your repair in that link.
Cheers

 

Quick update.
After checking the throttle body connectors over, they were clean, corrosion free and dry.
We swapped out the throttle body for a known good second-hand one.
While in there we found a cable .that feeds one of the injectors had burnt through partially.
The copper from one of the wires was possibly shorting to the underside of the charge cooler.
I had to cut about 1cm of it out, strip back and re-solder and heatshrink it.

The 2 combined fixes seem to have stopped the error and resulted in smoother idling and no hesitancy at low speeds.

For now it seems good. Will keep an eye on it over the next few days and report back.

In the meantime, both sides inner and outer sills are totally rotten out along pretty much all the length. That is the next nightmare to solve. At this point it will probably be cheaper to re-shell the car rather than fix the sills (and other holes) by welding this.

Oh well