OBDI Code P1797

2000 XJR With Almost 140,000 Miles. Drove Car Yesterday Morning With No Issues. Went To Drive In The Afternoon Upon Starting Had A Sever Seamed Like Miss. Has Code P1797. No This Morning Will Not Start Turns Over Fine Just Not Starting

CAN bus fault.
W5A-580.pdf (72.4 KB)
W5A-580_TRANS_OBDII.pdf (179.5 KB)
Check CAN bus integrity? (OBDII pins 6 and 14)

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Thanks For The Information But It’s All Greek To Me???

So you don’t want info and just wanted to let us know about the ‘no-start’?

I don’t think his response kind of deserved that reply: I think he just wanted us to know what’s going on and ask for some help.

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I think I provided some info.
He did not think the info helped?
(lead a horse to water…)

all he said was “it’s all Greek to me:” doesn’t seem to be someone who is ungrateful, just someone who didn’t quite understand what it all meant.

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Heck, I don’t even know what a C.A.N. is … :confused: ?

Well, from the materials Motorupman provided, this appears to be what the code pertains to:

P1797 No network token received
from ECM node.
No token received from
200ms None None 850ms 2 Drive

I would think this means that the transmission is not receiving (needed) input from the Engine Control Module for some reason. :thinking: Or was my Greek interpretation there way off ? :grin:

Don’t look to me for more answers. I don’t read, write or speak Greek.(only Jaguar and English)

LOL, Motor … sometimes we all wish we spoke “Jaguar” better than we do … :smile:

btw, any update for us on the physical recovery? Everything still going very well for you in that regard? :confused:

So With That Information Do I Need To Replace The ECU ?

That’s a transmission connectivity code that generates pops up while driving and limits gear selection / it would also come on in low voltage situations (bad alternator or battery), but usually doesn’t prevent starting.

I suspect it’s not your culprit but simply a byproduct of the same that has been stored in the memory.

First try a hard reset, pull off both the positive and negative battery cables and touch them together for 30 seconds to a minute (no battery in the mix obviously).

If that doesn’t work, which it may not, the fact that the car was acting funny ahead time appears to point a crank position sensor that has failed.

Hopefully that helps, and if you’re unsure on diagnostics for the same, it’s probably time for a trip to a local shop.

If it is the CPS, a big clue is the tach while you are cranking the engine - does the needle lay totally flat, or at least bob up and down a little? If flat, it’s CPS. :thinking:

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Tach Comes Off Of Zero Just A Bit

Does it at least have a little, noticeable bounce to it (i.e. up and down cycle) as the starter is cranking? If so, I’d say it’s not the CPS … :thinking:

Come Off Of Zero Steady Does Not Bounce

Wow … that IS odd … I wonder if that could be a clue/related to the no-start condition (whatever it may be) … :thinking:

Tried To Start A Bit Ago And Wants To Start But Just Won’t

Have you tried starting but with the accelerator pedal flat to the floor? Just spit balling that the engine maybe flooded. By flooring the accelerator the injectors are shut down, this allows the cylinders to clear excess fuel.