Cruise Control not Available - No Visible Corosion
 

Upon starting my 2004 XJR, I am greater with am amber light and the message, “cruise control not available.” Having read about water intrusion in the adaptive cruise control module, I removed the ACC unit from the car. By removing the module from the mounting bracket, I was able to remove it through the opening next to the fog light.

It appears sealed; there is no evidence of water intrusion or corrosion. There was also no evidence of corrosion in the cavity where the module is located. Absent evidence of water intrusion, I am hesitant to open the module as that will require destructive measures.

Any idea what the problem is? My iCarly and OBDWiz do not show any fault codes. Can one download SDD? Thanks.

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Corrosion or not, re-plugging connectors might help. Makes a new swipe on the contacts.

Thanks, Chris. I did that, and the warning came back along with “no forward alert.” I’ve ordered IDS. Perhaps that will shed light on the issue.

Otherwise, I was able to put the bracket on the module outside of the car, stick it in upside down, plug it in, and rotate it into place. Removing the fog light is easy and helps a great deal.

I don't have ACC. But I've read a lot about it in this forum (hint hint).
There might be other connectors. 90% or more of computer problems are connectors.

For sure you need to scan it by IDS/SDD. It can be box position angle out of range in the bracket or can link fail to ECM.. Thats's what i have seen so far in my car

good luck

Any other weirdnesses at any time? I mean any? I had occasional "Cruise not available" and "unable to set parkbrake" until I replaced my battery. The car is sensitive to undervolts of literally tenths of a volt. No messages since the new battery.

+ 1 on the battery!!!
Symptoms;
The car starts up, idle levels down, runs, & drives fine.
Shutting the motor off, on the restart, the warnings are gone.
A voltage drop test, should answer your batterys condition question