In case you ever wondered what the X300 ECU looked like inside:

STMicroelectronics EEPROM 512xx


See TSB :

http://www.jagrepair.com/images/TSB/...all%20R493.pdf

the 9355 labeled replaced eprom is for the 97 XJR and needs the matching replacement EGR valve # LHE 1550 AC

I thought yours was a 95 which does not have a EGR valve for the SC engine . Please clarify

I'm just saying ,

You are still open to barrow my voltage regulator for a week or so as I saw on your ELM 327 live data after contributor Vantveer put it in visual graph form

Editing

Mine is a 1997 XJR6, with EGR and it has had the R493 recall performed:

https://www.jaguarforums.com/forum/x...recall-126057/


But on that note, the ECU did not have the proper R493 decal attached after the work performed by the dealer back in 2015. I don't necessarily suspect that the dealer failed to replace the EPROMs with the updated recall EPROMs, but the case didn't show any obvious signs of being opened and again no decal. Does the "9355" label on the EPROMs indicate if they have the R493 updated EGR settings or not?

The 9355 IS the correct PROMS designation for the 1997 XJR.

bob

P.S. they are NOT EPROMS, they are PROMS (NOT Erasable)

Thanks, any idea if these are the R493 recall PROMs or not?

See page 16 parts list

http://www.jagrepair.com/images/TSB/...all%20R493.pdf

Blanks are avail about 4 bucks E - bay if you want to play

As Bob said, the 9355 PROMS are the correct R493 recall proms for the 97 XJR. They are listed in the TSB linked by Lady P. Yes, they should have put the updated PECUS label on the ECU, and they should have put a label up near the left hood hinge too. Oh well, labels don't matter much at this point. It looks like they did the correct work and now we know it. So probably no more worries on this subject!

Ah, it's funny..... you stare at something so long that you don't see it anymore

I've been reading that R493 document for years for different reasons, and most recently again this weekend as I moved PROMs around, but somehow I missed that table that listed the PROM numbers.... and I was looking for that!

Thanks!