So, I've been getting random fault codes based on poor communication among ECU's. My guess is the wire-based CAN buses, in a few cases, don't make solid contact with their many various sockets after so many years..

An example of codes is below. "Lost communication", usually intermittent. Disconnected the battery, pulled the connector on the Speed Control Module, cleaned it with contact spray and re-seated it a couple of times. Also confirmed solid grounds for the module. Codes cleared, no return. Problem solved. Also confirmed solid grounding while in there.

I've also seen a few of these "invalid data" conditions that might be originating in the instrument cluster. SO, now to the question: Has anyone here disconnected the battery, then removed their instrument cluster connectors and reconnected them without problems?

Yes, an abundance of caution question. Here's why. There's a warning in the maintenance manual that if the Cluster is to be replaced, the key codes for the old one needs to be cleared. I'm not doing that, just pulling and reseating connectors. My electronics background tells me that with battery disconnected, I should be safe disconnecting the two connectors on the Cluster and spraying them. But...it's a Jag.

Has anyone here removed their instrument cluster and reconnected the same one without problems?

Thanks!

 

Lots of people have disconnected any module (battery off) without trouble, just take care.

I wouldn't spray anything if the connector has that stuff designed to keep water etc out. (Not saying you would!)

If spraying make sure no residue left behind.

I'm more of the school of "inspect thoroughly, then most likely unmake & re-make connection a few times, spray nothing".

 

No problem with cleaning the instrument panel connectors. Just disconnected the battery immediately before removing. A note: there's a small black panel that's spring loaded against the top of the steering wheel hub trim. If possible, don't remove it. Mine was very fragile and snapped a part off. Good news is the part number is on it. Used replacement is the same as the XJ and a few others of the era, so easy to find and cheap.

Another note: none of these ECU communications codes triggered the light. Intermittent ones apparently don't. But they are a warning indication of degrading systems, so if you get one consistently related to an ECU, you might want to give it some thought for later reference.

 

I used to regularly get those two on my 4.2 XKR as well, along with many others. I think they are just side effect of marginal battery voltage and wouldn't waste any time trying to fix them.

 

Normally I would separate a plug and socket, spray with Deoxit D100 (or Deoxit Gold if there are gold plated contacts) and reconnect.

BUT

I find quite a few Jaguar plug/socket housings degrading to the point that they break or crack. So in this case I simply spray into the assembly and call it a day. The DeOxit will work its way in and clean contacts without damaging plastic.

This is a well-regarded product.



https://hosatech.com/press-release/why-use-deoxit/

wj

 

+1 on deoxit.