405s never go wrong ... oh sh*t

[carlo]

One of my 405s has decided to throw what I think could be an expensive wobbly, looks to be an immobiliser problem so don't know if any of you clever folk may have any suggestions.

 

I've noticed on a few occasions, which became more frequent, the car wouldn't start unless you locked it again, unlocked it then tried again.  Sometimes needed two or more tries.  I have bypassed/disconnected the keypad immobilisor without any issues, like I do on all my 405s so they start without needing to put any code in.

 

Wednesday morning it was flat as a pancake, eventually jump started it and left it running for an hour, although the battery light was still on suggesting a battery/alternator issue.  This morning it's back to it's old tricks, won't start at all despite numerous attempts at locking/unlocking.  I've even re-connected the keypad which seems to work i.e. putting code in turns it from red to green but the car won't start, and sometimes the keypad peeps for 30 seconds on red.  Looks to me like the battery draining has had a catastrophic effect on the immobilisor, which was showing signs of playing up anyway.

 

Spent a fair bit of money on this one too, but getting this looked at could be expensive, I fear.

 

 

 

[richardthestag]

1. you must be the very last person in the world who is still using photobucket

 

2. I have found that modern car systems rely heavily on a perfect battery and good charging system, I know you are talking 405 but..

 

Mrs Thestags C4 went batshit last year because the battery was a cell down, it was 8 years old etc so on its last legs, fitting a new battery did not stop the spurious messages and other Christmas tree lights, I disconnected new battery and left it for a couple of hours. while I topped up the battery on the charger. Reconnected it and it started fine and ran ok without stupid messages popping up. 

 

So check your battery is sound and make sure mr alternator is putting out 14.whatever volts when running.

 

sorry I know nothing about 405 immobilisers (are they not French estate agents?) but I hope you get him fixed soon

[tooSavvy]

^^^ don't waste £400 on a PhotBlockitt account either..

 

TS

[carlo]

^^

 

I won't, there's only a few pictures on it.

[tooSavvy]

^^

 

I won't, there's only a few pictures on it.

Flickr FTW m8

 

TS

[carlo]

Just noticed the ignition light comes on more brightly the more you rev the engine which to my limited knowledge looks like an alternator fault?

[Junkman]

Remember the blue GTX I sold to who is trying to sell it atm?

That one had the immobiliser that could only be immobilised by the key fob.

So for a while I lived in constant fear, that when the fob fails, J Davidson must be called.

I called upon one of those mobile car locksmiths, who came around and removed the

immobiliser in literally three minutes. From then on, I could unlock and start the car

no matter whether I used the fob or key.

[Junkman]

Oh, and can you please PM me how to disconnet the keypad?

[PhillipM]

I've had the same on my 406 - it was the contacts on the main fuel relay that had oxidised - the same one the ECU uses for the immobiliser function. Replacement was about £30-40 I think but I just cut mine open, scotchbrited the contacts and gave them a liberal slather of contralube.

[Mally]

I used to think 405's were the best car I've ever had, but mine never broke.

I think I love my 75 more now, but probably not for long.

[carlo]

Cheers, though I'm still a bit perturbed by the charge light glowing brighter under load which makes me think alternator problem, albeit a separate one!

 

JM - will PM you when I get back later.

[PhillipM]

That relay is fed/earthed from the alternator IIRC so it might also be the cause of the light.

[Jim Bell]

I think they all do this eventually. One I had did similar after the battery died and was replaced. Just a couple of times though. Freaked me out though.

[loserone]

When I get my 405 back, I'll make a little post and show you some of the pictures Scary has been taking of the process of fixing the blowing exhaust manifold gasket..

 

Last one was of a sheared head bolt - things may* have escalated.

[carlo]

Car has new battery, and seems to start happily every time.

 

However, charge light is on, and glows brighter when I rev it.  Perhaps I have cooked the alternator...