I need to replace this. It's been coding intermittently for a while and is now coding full-time.

Do I really need, as Jaguar says, to remove the inlet manifolds to do this? Is there no way to squeeze my way in, displacing the expansion tank, and get at it? I haven't tried yet - mainly because I haven't ordered its replacement yet!

Is removing the inlet manifolds as hateful as I imagine it is?

Secondly, I recall seeing an excerpt from a TSB at some point saying that a failure mode for this sensor was water getting into the connector via a hole under the panel in front of the windscreen, and saying this hole had to be taped over when replacing the sensor. Does this sound familiar to anyone, or did I dream it?

If I didn't dream it, it might be worth me trying to access that connector to check and clean it before I buy a new sensor.

Justin

 

Maybe change plugs under there at the same time?

 

The only correct, known way to access the sensor is by first removing the upper and lower inlet manifolds. Whilst replacing the sensor(s), it is also a good idea to replace the breather 'elbow' under the lower manifold as these are prone to fail causing DTCs for lean running and misfires.

If you have not already done so, obtain the Workshop Manual and become familiar with the procedure. Be sure to only attempt removing the inlet manifolds after a cold soak or the brass thread inserts will become detached from the manifolds. Use anti-seize compound on the bolt threads during reassembly.

Perform a search using the search function for this forum.

 

True enough, but according to the title, it's a 2003, so no vacuum elbow under the intake. That is one of the improvements Jaguar actually got right in the 2003 redesign. Contrast with the way they "fixed" the coolant expansion tank... or the suspension....

 

Since the OP appears to be in the UK, it may or may not have the elbow.

As far as the expansion tank; at least one does not need to remove the wipers, cowl and cross brace to reach it!

 

Can anyone tell me how different are the knock sensors called out for up to vin M45254 (XR84685 and LRA1692DB) compared with those for VIN M45255 onward (XR835380 and AJ85676)? The former seem to be cheaper and more readily available as third party.

If it's just a difference in the connector, I guess I could splice...

Justin

 

Could you give me a reference or part number for this elbow? I'm having difficulty identifying it using parts explosions etc.

 

Your car doesn't have one. The redesign was MY2002.5 in the UK, 2003 in the USA. 3.0L prior to those had the elbow cleverly stashed below the lower intake. For a good look at your vacuum lines, search posts originated by Joycesjag for "vacuum" and you'll find Rick's handsome tutorial with pictures.