1994 Jaguar XJ40 XJ12 6.0 from UK and Ireland


One of the most practical and feasible V12's


A Code 34 (VCM) which specifies a leaky fuel injector. This fault is still being assessed, but all symptoms point to it. The car is in limp home mode. With non-franchised specialists and good prices of parts from the USA, I am sure this will not break the bank.

The air suspension has been decommissioned by the previous owner due to an overhaul being too expensive to justify. The ride is fine without it. Also, I suspect that the specialist/USA parts sources will make the cost of recommissioning bearable.

The near side reversing light is dim, and despite fitting new bulbs, the "lamp out" warning light still persists on the dashboard.

The transmission fault light intermittently comes on at start-up, but if stopped and restarted several miles later, will not appear. Occasionally it will come on again on downhill sections of fast motorways. The fault light does not put her in limp home mode, but does make the gear changes very jerky. When starting up on cold mornings, the "clonk" occurring when selecting forward or reverse motion is quite alarming, and I often fear for the drive-train! I am sure this is going to cost a fortune...

The air con requires re-gassing too often - but this is a Jag thing. UK summers are not too troublesome.

The car will have done 150,000 miles by the end of the year, and all the usual items have been replaced, but the suspension has not been as unreliable as other contributors' cars have been. Touch wood...

The seat lumbar adjustment provides, but does not take away. Possibly a switch problem.

General Comments:

The car is, essentially a luxury cruiser with a dragster potential. It is not a high performance racer, and will not behave like one - especially round corners. The kickdown is phenomenally there when one needs it, or when one just feels like blasting the cobwebs away on a B road for a mile or two before returning to the famous "waft" that the Jag is famous for.

Fuel economy is as tragic as your right foot dictates. A gentle motorway cruise can see an average of 23.1, and a countryside blast or town shuffle can see that plummet to 8. The tank range is not as good as could be - 250 miles between £60 fill-ups can take the edge off touring.

Supremely comfortable front and rear, and the electric seats offer all necessary adjustment, and the exit/entry button is a hoot!

Basic but decent sounding stereo/CD.

Why does the front passenger not need a grab handle?

She sits very low, so speed bumps can be expensive exhaust-wise.

Would you buy another car from this manufacturer? Yes

Review Date: 5th June, 2004

28th Jul 2004, 04:00

To add to my review above: The fuel injector fault was in fact a coil fault - a very cheap and easy repair. The gearbox light was caused by a faulty terminal - nothing nasty or expensive. I should really up the reliability score by 2 or 3 points here. Still totally in love with the car.

3rd Jul 2015, 13:03

Which terminal causing the transmission light to come on was faulty? I'm having the same problem.

1994 Jaguar XJ40 XJ12 6.0 V12 from North America


A great car... but not for the faint of wallet


Part Failures: Transmission Seal, Oxygen Sensor (3 times), Air Pump, Rear Shocks (2 times), Engine Mount, Front Suspension Subframe Mounts, Front and Rear Shock Bushings, Front Anti-Roll Bar Bushing, Front Balljoints, Window Switch, Low Coolant Warning Sensor, Ignition Coil, Electric Seat Control, Radio/Tuner.

The car's suspension is obviously under-designed for the added weight of the V12 and the poor quality of US roads. The car has required replacement of suspension components that have failed or worn at a rate that is simply disgraceful. (I haven't totaled the suspension repair costs, but it is surely excessive) Particularly awful was replacement of bushings for the front suspension subframe. This is attached at three points, and two bushings were completely destroyed through normal use. This procedure was $2,000+. The heat from the exhaust pipes also appears to damage the rear shock absorbers at regular intervals.

The seal at the rear-most of the transmission was similarly baked by heat, and appears to be the one weak link in an otherwise fantastic and robust transmission.

The oxygen sensors have been replaced often; it seems they are just prone to failure (but they are not cheap).

The engine coil failed completely and without warning, stranding the car.

There are some interior trim noises over washboard surfaces and rough roads; more than expected considering the mileage and initial cost of the car. (The interior of my friend's 911 with 170,000 feels much better bolted together.) Also, the light cream color of the leather is unfortunate: it shows up marks and wears far to easily.

In 1994, JD Power rated Jags 5th in initial quality, which was a factor in my buying decision. I think, however, my car has not given much credence to such a high quality rating. After 160,000 miles, my previous Series 3 XJ6 was far more reliable.

General Comments:

Aside from the heavy repair/maintenance bills and disappointments listed above, the car has been wonderful. The engine is simply incredible, and seems to be as strong as ever, even with the high mileage. In fact, the entire drivetrain has remained flawless. The gears shift with perfect ease, and the sensation is that of a solid link between engine and rear wheels, not the somewhat fluid, mushy feeling of the older V12 with 3-speed automatic.

Most Jaguars have a special feel, and the V12 is certainly among the best of all recent Jags. I even prefer it to the new V8. The firmer ride of the twelve is a great compromise between comfort and performance, and when pressing really hard it resists understeer incredibly well. In Colorado where I live, mountain driving really shows up weaknesses in a car, but the XJ12 is just excellent at high speed and under strenuous conditions. Climbing step hills at over 10,000 ft., where engine performance is severely tested, it will just fly past traffic, even in top gear. It just goes where you point it, and gives an amazing sense of security and comfort. The only sore spot is fuel economy, which definitely suffers when going hard.

Inside, the car is the right size, with excellent visibility. I have read complaints of wind noise on XJ40s, but mine seems to be about as silent as possible.

Would you buy another car from this manufacturer? Yes

Review Date: 16th January, 2003

28th Dec 2003, 23:41

Auto Emission Recalls on Jaguar XJ12 and XJS.

About 3,000 of the Jaguar XJS and XJ12 for model years 1994 and 1995 are being recalled for oxygen sensor circuit failure, a device that ensures the correct amount of fuel and air are burned when the engine is running.