'07 convertible. Battery was replaced a year ago. I keep it on a battery tender. It's put on the tender every time I park it. I do drive it. Drove it all day last Saturday. All has been well, no issues. All of a sudden today, I get in to start it and nothing happens. Lights work, screen display comes on, FOB locks and unlocks fine (changed the battery in it, but no difference). I depress the brake pedal very hard but when I push the starter button, nothing happens. No click no nothing. Any ideas?

 

I'm sure you'll get many better suggestions shortly, but have you tried holding the start button and THEN pressing the brake pedal (with start button still held down)?

 

I have. I read somewhere to hold the brake for 20 seconds then try it. I'll try that tomorrow morning.

 

if you get absolutely nothing, not even a click, the starter could be toast. i guess the battery maintainer might have failed, but you seem adamant the battery itself is okay, did you already check it with a meter?

edit: oh yeah, and, the higher-amp relays in cars are usually audible when closing their circuit. i haven't had occasion to verify that in ours. so again if you hear absolutely nothing, maybe an ignition relay.

 

Remove, clean and reinstall both battery connections. A bad connection can do exactly that.

 

I haven’t yet. Had to be away all day. Shouldn’t be the battery, but who knows. I’ll check it tomorrow. Nothing would surprise me with this car. I may try tapping the starter with a hammer too.

 

Don't know why I didn't think about that. Happened lots of times over the years on some other cars of mine. I'll check that too.

 

or the switch on the pedal? No ‘clicks’ implies to me that the ‘start’ is not being invoked.
The fact that all the electronics come on implies there is electrical power.
If the pedal were depressed and the switch activated, I would expect ‘clicks’ with a non-sufficient battery.

 

I had something very similar just this week. Turned out to be the earth strap between engine/transmission and chassis.
I measured 0.3 Ohms across this strap - which seemed OK - but when I put a volt meter on the solenoid and the chasis, I got 0.25v when trying to crank the starter. I guess 200+amp was way to much for it.
Took one of my heavy jumper cables and grounded the transmission to the chasisis and the engine cranked and started OK.
Very happy that I hadn't sprung £100+ on a remanufactured starter/solenoid (plus many manhours to replace it).
Made up a new earth strap (from two skinny one from Halfords in parallel) and now all is good.

I think my old 07 XKR endgine mounts are probably a bit tired, and mechanically work this stap so many wires are broken - and all are badly corroded.
Definelty try to make a "good earth" between engine and chasis, as part of your diagnosis. May turn out to be something else, but this is not the first time a poor earth has caused me to puill my hair out.
Good luck.
MM

 

Went out to try her again...voila! Started right up. Now I'll be extremely nervous about driving until I discover the cause.

 

No-start happened to me twice a couple of years ago, and never since. Don't know why

 

Inadvertently pumping the brake pedal can make it hard to start. The brake pedal will feel very high and hard as a rock. You'll have to stand on the brake pedal with both feet and all your might to get it to start - and it might not. If it doesn't start, wait overnight and the following morning ...

Press the START button BEFORE you put your foot on the brake pedal. It should start with a light tap on the brake pedal.

If not, I'd start with checking the battery. See the Workshop Manual in the Stickies at the top of this Forum.

 

Blues, have you checked for codes? When my Start/Stop switch failed last year, I found that there were codes listed in the history. Changed the switch and all is good again.

 

I haven't yet, but will do. Thx

 

Curious, is the engine supposed to start cranking just by pressing the button? I hold it for more than a second before it starts cranking. But im not sure if that's normal...

 

I push the Start/Stop button first and then depress the brake pedal. The engine starts to crank as soon as the brake switch is made.

 

i'm pretty sure yes, but not as fast as you can go. one solid quarter- or half-second press. works the other way around as well; hold the button and give the brake pedal a quick but deep enough tap.

i've tried retracting my hand and foot quickly and the car indeed follows through and starts while i'm no longer in contact with either.

 

For the X150 to crank, both the START button and BRAKE pedal must be simultaneously engaged. It won't start just by pressing the START button by itself, regardless of how long you keep pushing the button.

The Owner's Handbook says to step on the BRAKE pedal first, and then push the START button. But as many of us have learned, there's a better way.

If you press the START button first, all it takes for it to crank and start is a tap on the brake pedal.

 

I have an 07 that occasionally does what you are describing. Pushing really hard on the brake normally resolves it. But I read someplace on this forum that someone tried locking the car, waiting a minute before unlocking the car - to get it to start. That has worked for me too. I have no idea if locking/unlocking or just waiting a minute is the reason though? I suspect its a combination of waiting a minute and brake pressure. But I also remember seeing a bulletin for early 07 cars - saying the brake pressure switch had to be recalibrated? But since realizing I have to push really hard on the pedal to start it, I don't think its taken more than two tries to start it in the last six months.