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So it looks like my 2013 model XK is having a starting issue. When I press the button I can hear the fuel pump engage, but that's all that happens. I've had my diagnostic tool on it and it's showing both break sensors on and its commanding the ignition and starter relays to activate. This is leading me to suspect either a dead relay, dead starter or earthing issues. I'm struggling to find where the earth strap actually is in the workshop manual, I'm planning on testing it by putting a jump lead between the engine and the chassis, but I'm struggling to find a good point to make the connections. If it does end up being the relay, I understand that it's soldered into the power distribution box under the bonnet, anyone ever successfully replaced it?
@Vehlin There might be an easy fix, if you're lucky.
Try pressing and holding the START button before you step on the brake pedal. Do that first thing in the morning, after the car has sat overnight.
I know that's the opposite of what it says in the Owner's Handbook, but trust me it works. If you inadvertently repeatedly step on the brake pedal, that "pumps it up" and makes it difficult to engage the brake interlock switch. You'll have to stand on that brake pedal really hard with both feet to get it to start when you press the START button.
If that doesn't work, you're back to Plan A that you described above. Good luck
It's about 2 months old, fully charged and the car is showing 12.5V from it. This happened last week, the car was completely dead and stuck at work. I randomly tested it on Friday and it started first time, I then drove it home, switched it off and the problem is back.
It's about 2 months old, fully charged and the car is showing 12.5V from it. This happened last week, the car was completely dead and stuck at work. I randomly tested it on Friday and it started first time, I then drove it home, switched it off and the problem is back.
12.5 volts is NOT a fully charged battery. Almost, but it's below the minimum threshold of 12.6 volts.
Perhaps... but I'm not that far along in the diagnosis to suspect a relay. Though agreed, if the start signals are being received...
You mention the battery at 12.5. What's the voltage at the Central Junction Box AND the Auxiliary Junction Box.?
Anyhow, As you asked, found these.
The ground should be easy to check, get under the front of the car and follow the ground lead on the starter. Next you need to make sure the solenoid is getting the start power. You mght have to connect a wire and run it to a volt meter where you can see the meter while attempting the start. Intermittent issues can be a pain to find.
What @Cee Jay said, if that doesn’t work:
- have the battery load tested. They can read full voltage, without having amperage capacity.
- mine will not start after I have it running on accessory mode. Seems the computers get confused.
Thanks for the info all. I'll have a crack at getting under the car when it stops snowing. Need to figure out where my multimeter has got to, I had a listen in the fuse box in under the bonnet and I can definitely hear the relay engage, which is good as that was one I was dreading having to change. I'm not convinced its the battery, before I changed the battery the car would show obvious symptoms that it was low such as sluggish starter motor and clicking when it was really low. I'm currently getting nothing at all.
Battery was showing as failed, but was brand new 3 months ago. Battery changed, still no start.
Starter motor changed, still no start. Jumped it with another car and it started right up. Seems it’s not interested in cranking unless it’s getting 14+ volts. So I’m suspecting some electrical gremlins somewhere.
Another possibility - check the battery cables. A bad battery cable can have high resistance and not pass enough amps from a single battery, but when you jump it, the higher potential gets enough juice through to start it.
Once the car is running, feel the battery cables, if one is hot, you need a new cable. This problem has been reported before in this forum.
I suspect alternator not putting out enough voltage to the batteries, Old and new one. When you jump start, where do you put the ground side of the cables? On the battery or frame?
I suspect alternator not putting out enough voltage to the batteries, Old and new one. When you jump start, where do you put the ground side of the cables? On the battery or frame?
Asked the mechanic this question and it was jumped directly off the battery. As for the alternator, it’s doing absolutely nothing on a car that isn’t starting.
Never jump start a 5.0L engine by connecting both jumper cables directly to the battery, as doing so can damage the Battery Monitoring System module that is attached to the negative terminal. Always attach the charger's negative (black) alligator clip to.a chassis ground. Because the 4.2L models (2007-2009) don't have a BMS Module, jumper cables can be attached directly to the battery (although it's easier to use the remote battery terminals in the trunk).
As mentioned above, the positive (+) remote battery terminal is located behind this plastic cover in the left side of the trunk.
Remove that cover to reveal the positive (+) remote battery terminal. Note that it extends through the bottom of that fender well, and is visible if you look under the car. You can attach your positive (+) battery charger cable or jumper cable either inside the trunk or under the car, whichever you prefer. Shown here with my red positive alligator clip to my battery maintainer.
The factory remote negative battery terminal is located in the spare tire well, and that's what I used for my battery maintainer as shown here.
Any "good" chassis ground will do, including the tailpipe.
Stuart
Last edited by Stuart S; Dec 14, 2024 at 01:54 PM.
A friends X100 wouldn't start. $2000 later of garage bills, and he had the same problem. Last week he changed the cable to the transmission to solve the problem.
We're back up and running! Ended up being a combination of a rusty earth strap and a loose electrical connection (somewhere). The battery was getting killed by the high resistance between it and the starter and alternator. So £900 later I've got a new starter, new battery, new earth cable and a running car.
We're back up and running! Ended up being a combination of a rusty earth strap and a loose electrical connection (somewhere). The battery was getting killed by the high resistance between it and the starter and alternator. So £900 later I've got a new starter, new battery, new earth cable and a running car.
Can you say where the rusty earth strap is located in the vehicle?
Starting Issues
