Of course, it is Christmas Eve, and on our first road trip since buying our 2004 XJ6, about three hours out on some of New Zealand's greatest driving roads, the Restricted Performance message came on (but with a yellow priority indicator whereas the owners manual says it pops up when red). At the base of Mt Ruapehu (Mt. Doom for Lord of the Rings fans), I am far from a garage with an OBD reader, so I am hoping by describing the symptoms, someone on the forum might have experienced them and give so advice. We're about 400 km away from home, it's raining and Christmas is tomorrow.

The first three hours were great. Perfect driving performance. Stayed on the speed limit at 100 kph even up the long upward grades, but the occasional full throttle to pass trucks going up grades. Filled the tank with regular (91) petrol (gasoline). Then driving up a long grade, with the transmission occasionally shifting down to keep up speed, the "restricted performance" warning message came on with an amber warning light. I reduced driving to about 80-90 kph, driving gently. At one point I tested with more power and the transmission began to shudder, which I presume is part of the restricted performance protection, so I backed off (not wanting to damage something in the middle of nowhere with spotty cell coverage). Driving gently there was no noticeable change in driving, certainly nothing like the disabling when my Mercedes SLK went into limp mode.

At the next picnic pullover, I parked and turned off the engine, but on restart the message was still there. Proceeding on, but now on level ground eventually the message went off. I kept driving gently. About 30 minutes later, we began the long grade up to the Central Plateau. I had a hunch that the additional pressure - even driving slower - would kick the warning on again, and sure enough it did, staying on until we arrived at our destination. I then pulled over on the road to our hotel, thought I heard a slight sound from the engine (hard to describe), but before I could find the bonnet (hood) latch to look at the engine, the sound quit and the warning went out. As it was raining and my wife was worried, I drove to the hotel where this morning I'm trying to work out what may have happened (still raining and the nearest garage is 30 minutes away with no certainty they would have an OBD reader).

Separate from this, I noticed earlier the yellow airbag warning light came on. It shut off about the same time as the warning, but then began to first flicker and then come on a while before the message returned. With a passenger and luggage on the rear seat, I reckoned it was just another debugging of a 16-year old car with 130,000 km (85,000 miles) on the clock, and probably not related to the performance warning, but I mention it in the event someone says it is related.

Because it happens only when pressing the engine more (up a long grade) the first two possibilities are:

1. It needs premium (98 octane) fuel and long-grade detonation kicks in the restricted performance. If so, solution is fill with 98 and buy octane booster.
2. Something is going wrong with the transmission and the pressure on it kicks in the restriction (actual, not just a warning).

We hoped to do 2-3 hour road trips from our base in National Park each day, but not if it means we destroy something. Looking online, everyone's first answer is to get the OBD error codes, which is not an option. Thankfully I do have roadside assistance, but rather not have to use it, especially on Christmas.

Any thoughts on other causes given the facts - comes on at 75-100 kph sustained driving up long grades? Goes off when back on level or going down hill - but only after several kilometres. Amber warning, not red. No "Engine Systems Fault" or other drive train warning or light. Possible connection to yellow Airbag warning light, but unlikely.

 

Well that is rather unfortunate.

Based on what you are describing it could be the transmission fluid heating up and the fluid being near end of life per the software. Not sure if Jaguar uses similar software to Volvo. Volvos will code out when their transmission fluid has hit a maximum heat mark three times. At this point the fluid needs to be changed and the counter reset.

Any knowledge of the fluid level and whether it has been serviced? What is current mileage? If I recall on my USA 2004 XJ8 the service interval for the transmission fluid is 105k miles. Do you see any signs of transmission fluid leaks? Look for signs of leaks at the oil pan gasket, coolant lines (from the engine bay looking down find the lines that go to the cooler coming up from below) and at the wire harness plug where it mates to the transmission.

 

Just guessing but it sounds like low ATF to me.

It drives ok on the flat and problems occur when going uphill.

You could down load Torque Pro on your phone and look for codes.

BTW 91 octane is too low.

 

I had a Restricted Performance situation similar to this a while back. It came on after a long gradual hill at highway speed when the car was pretty new to me, but sill 12 years old. It was gone on the next start up and didn't come back for 6 or 8 months, but that may have been because I didn't encounter any more long hills at speed in between. When it did come back, it kept coming back. It was eventually tracked down to the MAF sensor. Changing that fixed the problem. I don't know how different the V6 is, mine's the SC V8, but the symptoms are pretty similar.

 

So we have two theories and no tools. Theory one is transmission fluid - visually he can check for leaks and if he sees none that is a plus.

Theory two is the MAF. If he unplugs the MAF will the Jag go into Close Loop mode? On my BMWs that is what will happen, not optimal but a means of testing.

 

Lets all hope the low grade fuel is the source of your issue, always use a high grade fuel !!!!!!!!!

Get caught up on all the neglected maintenance items on the car.

Spending quality time, getting to know your cat, can pay big dividends

A Jaguar specific reader, is really a must ,to see what's going on.

 

Octane numbers seem to be a variable that changes by geographical location. I'm from the west coast in Canada. Tier 1 stations offer fuel starting at 87 (regular), 89 (mid-range) and 91 (premium). Chevron also offer a 94 octane grade. Doesn't the UK use the RON grading system? The point I'm making is one cannot conclude that 91 octane is too low. It may or may not be depending on location.

 

I had a similar problem with my 2004 X350 XJR.
I flushed the transmission and refilled it with new fluid.
Problem solved.

 

As an easy possibility go the premium grade of fuel route. If the octane is too low on a long grade the engine will knock. The ECU will try to retard the ignition enough to stop the knock. However there is a limit to how far it can retard the spark so restricted performance will kick in if it still knocks at limit..

 

In the USA the R+M highest octane at 90% of the stations is 91 and has been for at least 20 years. I believe this is why there is a difference in VIN selections for (US, Canada & Mexico) as the ECM has different fueling maps to compensate for the R+M Octane rating in North America.

I'm pretty sure my owners manual for North America says 91 is sufficient in each of my XJ's from my 1996, 2000, 2001 and 2005, but I'll go back and recheck. In any case it is about moot because the highest can find is 91 unless I go get racing fuel or aircraft fuel, or trust the octane booster additives to actually do what they say for the ratio booster to fuel.

 

SOLVED. Kirk Automotive in Taupo agreed to stay open on Christmas Eve. A quick scan on the OBD told the story. The dirtiest MAF sensor he had ever seen. BTW, the transmission was properly serviced a month ago. New filter, not a flush but a proper redo. If you live in NZ and are looking for a competent mechanic to sort your X350 (or whatever) Mark is the best I have found. Mark Kirkcalaldie of Kirk Automotive. Ring him on 027 200 2570, but wait until after Christmas... and he is right around the corner from The XJ Shop Limitedthat specialises in older XJ jags.

 

North American (R+M)/2 91 octane is the same as RON premium in the rest of the world which appears to have a considerably higher octane. Not sure how many other countries use the same one as NA. You are fine using NA 91 octane.

 

Sunoco's top grade used to be rated at 96.5, my 1973 Triumph 750 Tiger called for 96 as a minimum rated fuel

 

The best we can do in Canada is 93, unless we go to the airport and mortgage the house for a tank of higher octane.

 

Hi x350,

If I understand the sequence of events, the RP occurred after refueling about 3 hours into your trip. Is it possible you got some petrol contaminated with water?

It might be worth adding a couple of bottles of petrol drier to your tank. In the U.S., the most prevalent brand is Heet. Most of these products contain methanol, which helps the water and fuel to emulsify so the mixture can burn in the engine.

Cheers,

Don

 

Hi x350,
As another New Zealand member, I agree with the recommendation to use high octane fuel. The grades here are 91, 95 and 98 RON. I have not had a V6 x350, but the NA V8 engines have a compression ratio of 11:1 which could make use of 91 problematic. I also experienced 'Restricted Performance' issues, but these were related to a non-operational supercharger coolant pump. It's certainly an unpleasant experience.
I only use 91 in my little Toyota Rush/Terios. My 2 litre Mazda Capella DOHC and the XJ12 HE, and of course the Super V8 all need 95 or better.There is a sticker inside my V8's fuel door (in Japanese) stating this.
I hope that cleaning the mass airflow sensor helps, but carry on with the other maintenance tasks, most of them are well within the average owner's capability.
This forum (and 'ahem' the other one) is invaluable. I have bought the iCarSoft LR V2.0 scanner, it was about $300, but is excellent. Make sure you join your local Jaguar Drivers' Club too, and also the Daimler Lanchester Jaguar Spare Parts Club, here in Christchurch.
All the best for your trip, but the real scenery is in the South Island!

 

I trust when a person talks about fuel grades they are not implying a "better quality" of fuel as the octane increases. This is a good link for a better understanding of the variables involved.

https://www.eia.gov/energyexplained/...e-in-depth.php

 

Hi Pete,
In regard to the real scenery, I agree, South Island is amazing. We're thinking of taking a long tour in February when Kiwis are back at work or school and the weather is at its best.

Thanks for the tip on the iCarSoft scanner. There are so many choices, it's helpful to hear what actually does the job.

On the petrol grade, it's really hard to get facts. Finally, I found this article that speaks to NZ grades of petrol: https://www.canstar.co.nz/car-insura...hould-you-use/ . Checking my petrol tank cover it says "unleaded petrol only" . The article says " If you open the fuel flap of your car and it says “unleaded petrol only” it means 91 octane fuel is okay to use. If it says “premium unleaded only” it means you need to use at least 95. If the fuel flap tells you to use 98, you use 98." Is Canstar right?

The XJ6 V6 3.0 engine has a 10.5 compression ratio, lower than the 11:1 in the V8's. This New York Times article also discusses the question: https://www.nytimes.com/2016/09/23/a...r-regular.html

 

A friend, who worked as an oil, & fuel salesman, told me all fuel was the same till after the additive package.

Oil is all about 30 weight when as it comes from the ground, also until the additive package goes in.

 

Hi X350, good to get it all sorted out. I have always thought that you multiply the compression ratio by ten to get the best octane rating, but that is from before fuel injection and engine management computers.
Here is a pic of my fuel cap, sorry, this is before I cleaned all the tape off. I used Google Translate to read the top sticker and it apparently says "lead free premium gasorine" I kid you not.
Send a pm if you are coming past this way!

lead free premium gasorine