I had to do a 200 mile round trip last Wednesday in probably the worst driving conditions I can remember. There was just so much standing water on the road and the 80 mph wind was driving the spray sideways across both carriageways
Anyway, after about an hour of this I noticed the power was briefly dropping slightly and then coming back again, causing a surging effect. I initially thought it was the buffeting from the wind, but then both red and yellow warning lights came on, no trac avail, no ASC avail and then all power went and I had to coast into a lay-by. The engine was still running but it felt like it was on four not eight cylinders and I had to use a bit of force to move the gear selector out of D. The reason for this was the engine was idling at about 1500 rpm and rough as you like.
I shut it down and restarted it after a minute and all was well and there was nothing to indicate a problem. The same thing happened once more after another twenty minutes and again, it re started fine.

The rest of the trip there went OK and I got back into the car about eight hours later and everything was fine for the trip back.
I used my Autel OBD2 tool to check for codes and there were no active codes listed and only P1000 listed as pending.

Anyone got any idea on what happened and caused the engine to behave like this, why there are no active codes and is the P1000 normal. I understand from JTIS this would indicate that the 5 diagnostic monitors have not completed their drive cycles. How long should this take?

Thanks,
Andy

 

Andy,

I know you've been having extreme weather conditions down there which almost certainly exceed the wet weather testing carried out by Jaguar during development!

The Trac/ASC will probably have been caused by water getting into the wheel speed sensors.

Odd behaviour from the transmission could be down to high pressure water blasting the rotary switch on the side of the transmission.

I've once had a similar power loss after going through flood water in an X308. The only thing I could put it down to was rapid cooling of the cats throwing the fuel trims off. This could well be wrong but it never happened again and I didn't give it too much more thought.

The P1000 is strange if you haven't cleared the codes recently. As I recall, you've been using your Autel for a while so presumably no one else has worked on the car and had reason to clear DTC's?

If you don't deliberately do 'drive cycles' to complete OnBoard tests in as short a time as possible, they will complete themselves as you drive normally in a few hundred miles.

Graham

 

Thanks Graham. I like your thinking about the cats cooling down and upsetting the fuel trims. Presumably if the trims go too far off base and completely out of range, then the ecu can't account for that and it goes into restricted mode?

I think the transmission issue was more to do with the engine running at about 1500 rpm, so the transmission was loaded and therefore reluctant to allow the lever to be moved out of gear. Again, this is only my best guess.

The conditions on the return trip were much better - if you ignore a complete white out in less time than it takes to say 'Holy S**t!' - and the can ran faultlessly, so it appears it was definitely? related to excess water under the vehicle and in the engine compartment.

I will check the fuel trims when I get a minute and see how they look. I looked at them not long ago and both the LT and ST trims were looking good.

Thanks,
Andy

 

I try to give the ECM as little thought as possible as it always conjures up nightmare visions of £££'s but that seemed a reasonable explanation for the sudden restricted mode.

Once the South West of the country rises above sea level again you'll likely never see a repetition of this rather unnerving power loss.

Graham

 

You are right, I think it is a good explanation, but if a situation was created that was out of range for the ecu to compensate for, why are there no codes?
Andy

 

Worry about that P1000. If you haven't cleared the codes recently then some event has. Most likely would be a power loss to the PCM, and that would really want investigating (in the dry!).

I think the 1500rpm would be the PCM trying desperately to keep it running. Probably open loop. I know it was running badly but the PCM tries not to shut it off which can be even worse.

 

Hi JV8,
Thanks for your input. I'm less concerned about the P1000 as I did clear a code a few weeks ago which I'd forgotten about and the car has probably only covered 200 - 300 miles since then.

I've been trying to cast my mind back to that particular incident, which also occurred in very wet conditions and from memory, the check engine light came on but there was no adverse affect on the vehicle performance. When I got back I checked the code (I don't remember what it was) and it was to do with a lean condition on one of the banks. I cleared the code then and haven't had any other trouble until my last boating trip on Wednesday.

I think I'll keep an eye on it and keep checking the pending codes. Presumably once the drive cycles are complete the code will change to P1111. Would this be correct?

What I still don't understand is why the events on Wednesday didn't generate any stored codes. How do we explain that?

Thanks,

Andy.