1996 Convertible - 4.0 AJ16.
Is there a way to determine if the ECU has been replaced?
Is the original Serial No. recorded anywhere?

 

Not sure about a '96.

On older models, at least, the ECUs had a paper tag with a part number and sometimes other tags as well. I've seen some that said "remanufactured" or similar. In many cases Jaguar part numbers have an "R" suffix to indicate a "remanufactured" part. If you similar tags on your ECU you can be sure it has been replaced. Lack of such tags, though, probably shouldn't be taken as proof that it hasn't been replaced.

Others will chime in

Cheers
DD

 

There is usually a date code on the ECU sticker, it should be reasonably close to the manufacture date of the car.

 

The earlier date is 04/01/00 - I'm thinking this might have come from a newer X300.

 

The manufacturing date on the original was the 24th week of 1999. There was a revision to the EPROM ( which is a chip replacement) done in 2001. It was fairly common to have chip replenishment, there was a number of updates done over the years, I think primmairly for emission reasons to do with the EGR.

 

R493 RECALL,RECALL,RECALL,RECALL,RECALL,RECALL,RECALL.

We were to perform the RECALL on all cars that came into the dealer when the R493 was issued.
I did DOZENS of these on the AJ16 engine cars!!!!!!!!!!!!
The labels were applied at the time of the PROM replacement.

There might have been a PROM replacement (04/01/00) prior to the R493 but we replaced the PROMS with the latest regardless of prior replacements.

It is NOT an incorrect part.

If you suspect an incorrect PROM, remove the covers and check the PROM number as per the TSB (9360)

bob

 

Good info. Thanks.
So, as the original build date is 1999 it can't be the original ECU but it is a correct ECU and should be a good, functional replacement.
Is that a correct assessment?

 

The original ECU might have been replaced under warranty (4 years/50k Miles), then updated in April 2000 and then the R493 chipset manufactured in August 2001.

Looks 'legit' to me.

bob