I apologise in advance for a long post, I'm having some strangeness happen with what I think is the security module.

Drove to work all ok on Wednesday, parked up, and locked with the fob. Five hours later went to pop out on my lunch break and the key fob didn't work. I thought it might be the buttons getting lazy, so used the key, the central locking fired and opened all the doors, rushed to put the key in the ignition and realised that no chimes to warn me I have 7 seconds to comply. Dashboard comes on, and no warnings, but she refuses to turn over.

A couple of things I had noticed Tuesday night though, doors seem to operate the central locking randomly while driving, and the tick tock sound when the indicators work goes at double time which I thought meant one of the bulbs has gone, but all are ok when checking. Driving in to work Wednesday morning and all back to normal haven't had any of those problems since.

I called my breakdown service out as I thought it was the battery and no-one at work had jump leads. The breakdown guy had a look and he tested the battery and said it was ok but just needed a charge. So he connected his booster, but it still wouldn't start. We then realised the immobiliser wasn't deactivating. He said then an ECU reset should sort that, which got the car started, but fob still isn't working.

There was a bit of water in the spare wheel well so I've dried out the interior of the boot (trunk), checked the slcm for shorts etc and it's all ok no burnt out bits. I had to lock it Thursday night with the key as the fob wasn't working and assumed I had to reprogram as had disconnected the module. Thought to myself, I'll do that in the morning. Well yesterday morning without me having to do anything the fob worked! Drove to work and parked up. Fob not working. Locked car up and left it until my lunch break. Went out, fob working again. Drove it to local Tesco, turned car off, fob not working again, went back to the car fob still not working. Got back to work, locked the car with the fob! Came out after work fob not working. Unlocked it with the key, engine wouldn't start, immobiliser still active, opened the boot with the key as the growler button didn't work (although this morning it was working), to disconnect battery and reset ECU and the alarm went off. I put key in ignition to turn off alarm and the car started!

This morning, had to unlock with the key, got the chimes to get the key in the ignition and she started all ok, drove to work, went to open the boot with the button on the dash, which is working, and the display is showing Valet Mode and I get the chime. Had to unlock it with the key (no alarm this time).

It's driving me absolutely batty! Does anyone think it would be worth looking at replacing the SLCM? Or could suggest what else I should check?

 

Is the battery fully charged? 12.6 volts after night standing?
Have you changed the batteries in the fob?
Have you done a scan to see if any codes are present, whether showing on the dash or not?

Car details please.

 

Hi Steve,
Thanks for the reply.

It's a 2000 X308 XJR.

Batteries in the fob have been changed and contacts cleaned.
Have scanned for codes and have a lambda sensor intermittent but that's all
The battery is at 12.35V, but hasn't had a charge, so will be doing that overnight tonight.

 

Welcome Jimbo, please be sure to introduce yourself and your Jag in the New Members Forum (top left task bar, ..Forums, ..General Jaguar Forums, ..New Member Area). Check with your regional forum for any events if your interested in such.
I believe you are chasing ghosts, and low battery will create them, 12.6 isn't very good for a battery. It should be at 13+, more to the 13.8 area. How are your cables? If you have any corrosion, replace that cable(s), it is minimizing your batteries ability to be charged and to provide start up procedures for the electronics. Check your grounds for rust/corrosion. Moisture in the boot is not good, it should be dry, that leak must be found and corrected. Check your MEGA fuses just in front of your spare (MEG250XP), be sure they are clean secure. They are somewhat difficult to diagnose, but are relatively cheap ($8 ea. US) to just replace. Remember your dealing with 18 yrs old parts, so don't doubt a failure on any of them.

 

Try a Hard Reset as something maybe got out of sequence so you would be putting it the SLEU back to zero state . Engine ECU my have to learn on it's own the parameters it may lose . A secondary problem may be the switches in the Fob may be intermittent and can be replace in the link below : You'll have to open you FOB and see if they physically match

Jaguar X S XJ XK XJR Type 4 Button Remote Key Fob Case Repair Refurbishment Kit | eBay

 

Hi all, as a new member also, I'm reading this thread with much interest, but I don't know the acronyms, I'm useless at texting too LOL.
What is an slcm and sleu, and a growler? I need to buy Jags for dummies.
Clive

 

Sounds sooo much like a battery on its way out.

Or possibly bad power/ground connection. (But 98% it's the battery.)

 

2011 XF - For the past six months both of my key fobs have worked intermittently and inconsistently. A few days after I install a new battery in one, the display will say that the remote's battery is dead, so I have to use the manual method to start and open. But it all may work the next few days. Could it be related to the car battery going bad or could it be the sensor unit in the car?

This sounds like another weird electrical problem that would cost me $800 to fix. Makes me wish for my old reliable Toyota.

Advice?

 

My advice would be to post in the XF forum to get a more direct answer from those with XF's (this is the XJ 308 forum). But as an overall statement, bad/low batteries in any vehicle will create scenario's not commonly encountered.