Details for Jag mechanics:
I was diagnosing code P1638 step by step and found that instrument cluster is bad.
Step G195523t35 (from ALLDATA)
Resistance is checked between data link connector pin 6 and 14 (yellow and green wires)
If resistance is between 50 and 70 Ohms, cluster is bad. Please verify if you have real Jag manual.

For all:
I'll go and get cluster tomorrow. Questions:
Which year to which year fits? Mine is 2003(not 2002.5)
Will engine start with "new" used cluster?
Where is odometer mileage memory? Which mileage will it show?
Thanks.

 

Do not connect another.

If you try to start it will go into anti-theft and you'll need a dealer tool to get it out of that.

What ohms do you have? As you can see from the electrical guide, the CAN terminators are in PCM (aka ECM) and ICM and 120 each (so in parallel 60). They're resistors and not prone to failure whereas connectors, wires, etc all are.

2002.5 (UK) = 2003 (US)

 

Big +1

 

Thanks for your responses! Very important info!
Resistance was about 55 Ohm.
I am including test 35 from ALLDATA.
Please verify it is wrong.

I spent a few hours trying to download JTIS21. Unfortunately it doesn't work. About a week ago I successfully downloaded on my dad's computer, it worked fine.

What is normal CAN voltage?

 

I went to a Jag dealer to talk to mechanics. They said most likely bad instrument cluster and showed a box with 2 cluster, I guess 04-05, gauges were full circle, not semi circle(03).
BTW, instrument cluster says "Ford". Fords around my year (03) take used clusters with dealer programming.
I'll check P1638 code for 03 LincolnLS, possibly better description

 

For CAN just do a web search and read

55ohms isn't far out and I expect is OK. It's used for specific reasons you can read about if you really care LOL.

 

I uploaded a copy of my Student Guide MULTIPLEX SYSTEMS. It has all sorts of info but it is over a decade old. It should have answers for your era of car.

bob

 

Dealer mechanics programmed another speedometer, charged me 1 hour for programming and $135 for second key which I didn't have and they needed for programming.
My Jag was parked for about 8 months, I didn't have time to deal with it.