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I have had this issue for 3+ years on my Jaguar 1996 XJS...No one knows of a fix

I have a 1996 Jaguar XJS 6cyl. I can not pass the inspection, because the technicians get a constant “Monitor Not Ready”
I have been to a handful of mechanics (including the dealership!) and they do not know. Yes, I have had this issue for 3+ years now, posted on numerous jag forums, etc.

The monitors that are not ready include:

O2 Sensor -Not Ready
Catalyst-Not Ready
Secondary Heat Sensor- Not Ready
Evaporation System- Not Ready

I have done the drive cycle for the car (It is a very cumbersome procedure but I have done it multiple times, still no change). Also I have put over 35k on the car over a period of 3 years and the car still wont go ready on these codes. Each year I have to go through a month long process to get a waiver so I can renew my registration. I only need 2 of these codes to go ready (state of NC allows 2 not ready codes on 96-01 vehicles).

I would appreciate any help.


The car is old enough that you may need to clean the electrical contacts for these sensors. If you already did that, has the ECM been replaced? parts of it may not be functioning. Cleaning the contacts is cheaper. Start there.

No ECM hasn’t been touched. Aren’t there multiple ecm/ecus? And if it was a dirty sensor, wouldn’t it just throw a code?


Do you know if the power lead for the ECU memory has been checked out to make sure it is getting proper power when the ignition is off?

^ I know that it hasn’t. Any tips on going about doing that.

If the PCM can be reflashed, have it done. Sometimes it fixes everything. Maybe the data is corrupted.

In order to find out what lead ties to the memory you will need a wiring diagram. You could try doing a web search and may get lucky there. You could also try checking out forums for Jags that may have the info.

Thanks, unfortunately there isn’t much information on these types of vehicles, but ill keep looking around

Here is a link to one of a number of them that are available on Ebay.

Thank you, will look at that

The best website I’ve ever seen for Jaguar maintenance and enthusiasts, there’s a tremendous amount of information here: