** NEW QUESTION! ** I didn't want to start a new topic so I thought I'd just use this existing one. I'm planning on trying some immobiliser resync routines I've found on this forum, but before I do I was wondering if there's anything to be concerned about when unplugging the battery. Most of the time I read about disconnecting the negative lead only, but in one case the guide says to disconnect both. ==================================================================== Anyway, what I'm wondering is - should I be concerned about how long the battery is left disconnected? Are there any systems in the car relating to the alarm/immobiliser that would mess up if I left the battery disconnected? I guess if there are then it's probably not much use worrying now as the car's been sitting out there with the negative terminal disconnected for over a week (I wanted to conserve battery power while the car was sitting idle and unrepaired). I would've thought such important things as transponder codes and the like would be stored in some sort of rom that wasn't affected by power loss. ==================================================================== OLD BIT: Hey all, just signed up as I've been poking around on here since I started driving my big bro's Carina about 5 months ago. It's a Carina E 1.8 ('97 I think, R reg anyway), 120000-odd miles on the clock. Yesterday on the way to work suddenly the engine just cut out. My initial thought was I'd stalled it but the radio and electronics were still on which doesn't happen when it stalls. While the car still had momentum I managed to roll it onto the pavement and luckily enough this happened a hundred yards or so from a mechanic :) I tried starting it again but there was no response at all when turning the ignition. Nothing. Not even trying to turn over. No ticking like what I've heard when the battery is too low. Complete silence. The only thing different between the key in the 'on' setting and the ignition setting is that the airbag light turns off. Oil level is fine, coolant, water, etc, all check out. All the electronics were still functioning fine - lights and radio at least - and when we wheeled it into the mechanic's garage he faffed around with it for about a half hour or so. Connecting the battery directly to the engine caused the engine to start up but it wouldn't turn over, similar to when you try and start a dodgy car when it's cold. That meant that the engine is probably ok (mechanic's initial thought was that it's the timing belt or something like that) A friend of mine is a qualified Toyota mechanic so I got him to speak to the guy on the phone. The mechanic thought it might be something to do with the immobiliser, but my friend wasn't so sure. Nonetheless, seeing as the mechanic wasn't too sure what to do next, he towed it back to my house where it's now sitting out there all alone :( He said to try unplugging the battery overnight to see what happens, which I did. My friend said he'll pop round some time this week, but I wanted to fiddle about in there anyway to see what I could find out in the meantime. I tried resyncing the keyfob to activate/deactivate the alarm in case it was something to do with the immobiliser (our keyfob's a bit dodgy, sometimes it won't lock so I just use the key to lock/unlcok the car) and tried the ignition again, but no such luck. Then I got hold of the diagnostics codes from here but here's the problem: The diagnostics mode (bridging TE1 and E1 together) causes the engine check light to flash a certain number of times (or to simply flash continuously if there is no fault) which is fine, but in my case the light isn't flashing at all. I have a feeling it's because the engine itself won't turn on. Also, the green ECONOMY light that used to light up when we first got the car has since ceased to function for a good few years now. I'm wondering if maybe the fuse for it went and also the engine check light along with that. Does the diagnostics mode not work at all if there's a problem with the engine? Also, does anyone have any idea what sort of things would cause this? My dad was googling when I rang to tell him the car had broken down and he read that it may be something to do with the ignition coil. So as it stands the possibilities seem to be: 1) Immobiliser 2) Ignition Coil 3) Something else The problem with (1) is we're not even sure the car actually has an immobiliser. It's not mentioned in the manual, anyway. Supposing it did, is there a way to bypass it? If it's sunny outside in the morning I'm planning on poking around the fuses with my voltmeter to see if any have been damaged. I was wondering if there's a way to read the fault codes without the use of the engine check light, i.e. can I hook my voltmeter up to one of the pins on the diagnostic connector to figure out the codes (seeing as it just sends voltage pulses to the light anyway)? I checked the battery and it's reading 12V-odd. I also had the radio on (quietly) while being towed back and it was fine. I also have the Haynes manual for my car, and will be using it to check the fuses. Even if I don't find anything, at least when the professionals do show up I can save them time by having checked all the fuses already! Thanks in advance for any replies, even if it's just speculation!