Saxo ECU

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Post Reply
luke6040
Posts: 4
Joined: 24 Feb 2010, 10:58
Location:
My Cars:

Saxo ECU

Post by luke6040 »

Hi my ecu is dead on my 2001 1.1 saxo (its the 3 plug type) i tried to replace it with a new (second hand) along with the black box and key but the immobiliser just kicked in. Just wondering if there is a correct way to fit it before i try another new one?

Thanks for the help.
Luke
User avatar
Chris570
(Donor 2020)
Posts: 1461
Joined: 12 Dec 2009, 14:10
Location:
My Cars:
x 29

Post by Chris570 »

i'm not brilliant at saxo transponder immobilisers but i think the transponder pickup ring is linked to the key?
luke6040
Posts: 4
Joined: 24 Feb 2010, 10:58
Location:
My Cars:

Post by luke6040 »

OK got the new ecu fitted and running, well sort of. The car is still missfiring badly, has anyone got any ideas what is wrong??
User avatar
Chris570
(Donor 2020)
Posts: 1461
Joined: 12 Dec 2009, 14:10
Location:
My Cars:
x 29

Post by Chris570 »

check its firing on all 4 cylindars check sparks and fueling, the coil pack is split into two halves so if it sounds like a lawnmower its most likely the coil pack
citronut
Posts: 10937
Joined: 29 Apr 2005, 00:46
Location: United Kingdom east sussex
My Cars:
x 92

Post by citronut »

as Chris says the coil pack is the first thing to check, as it is a common fault,

why do you think you old ECU was dead,

were abouts are you

regards malcolm
luke6040
Posts: 4
Joined: 24 Feb 2010, 10:58
Location:
My Cars:

Post by luke6040 »

The recovery guy and a mechanic said it was the ecu, but clearly not. ther is spark on all four and fuel to all four but I'd swear it's not running on all four. Could it not be sparking under compression? I'm in Wolverhampton.
luke6040
Posts: 4
Joined: 24 Feb 2010, 10:58
Location:
My Cars:

Post by luke6040 »

luke6040 wrote:The recovery guy and a mechanic said it was the ecu, but clearly not. ther is spark on all four and fuel to all four but I'd swear it's not running on all four. Could it not be sparking under compression? I'm in Wolverhampton.
Just to add to this, im getting a coil pack today to try so will let you know, also as i have changed the ECU i use a new key to start the car, am i safe to have the old key near the ignition barrel?
User avatar
spider
Posts: 3949
Joined: 05 Jan 2010, 14:28
Location: Derby.
My Cars: Soon, I hope...
x 77
Contact:

Post by spider »

You need the key body of the correct key nearest the aerial around the ignition switch.

You could take the blade out of the new assembly and just hold the "correct" body near the aerial and turn the new key with pliers etc if needed.

Keep the "wrong" body away from the aerial, you do not want to confuse it.

As far as I am aware, as long as they transponder in the key body matches the code in the ECU (hence it important to get the key with a used ECU) its good to go.

Can be programmed in most cases to accept new key codes, although need Diag / Lexia to do this.
Andy.

91 205D-Turbo, gone but still missed
02 106D, TUD5B, gone but not really missed apart from the MPG
User avatar
Chris570
(Donor 2020)
Posts: 1461
Joined: 12 Dec 2009, 14:10
Location:
My Cars:
x 29

Post by Chris570 »

if you've got fuel and spark in all 4 cylindars you engine would have to be shafted not to run on all 4, try the old trick of removing one HT lead at a time (engine off) and then seeing which one makes a difference, et voila dodgy cylindar found
wheeler
Posts: 6848
Joined: 21 Sep 2002, 19:07
Location: United Kingdom
My Cars:
x 717

Post by wheeler »

How are you checking the spark & fuel ? Are you getting an injector pulse at all 4 injectors ?
spider wrote: Can be programmed in most cases to accept new key codes, although need Diag / Lexia to do this.
You can't do this with lexia, all citroen ECU's (with transponder) & imobiliser 'black boxes' are programable only once, the code cant be changed.
citronut
Posts: 10937
Joined: 29 Apr 2005, 00:46
Location: United Kingdom east sussex
My Cars:
x 92

Post by citronut »

Spider they dont have HT leads as they have a coil pack which sits right across all 4 spark plugs, also you should not use that old trick to test which plugs/cylinders are fireing, becaues if you create to biger spark gap you can damage the ignition module,

regards malcolm
User avatar
Chris570
(Donor 2020)
Posts: 1461
Joined: 12 Dec 2009, 14:10
Location:
My Cars:
x 29

Post by Chris570 »

my bad on the coil pack, didnt read the year
User avatar
spider
Posts: 3949
Joined: 05 Jan 2010, 14:28
Location: Derby.
My Cars: Soon, I hope...
x 77
Contact:

Post by spider »

wheeler wrote: You can't do this with lexia, all citroen ECU's (with transponder) & imobiliser 'black boxes' are programable only once, the code cant be changed.
Well, I learned something new. The pug 106's can be re-coded as if you order a new key (inc the body) you simply recode it via the Diag... You do need all the keys though to do it as it will forget any you do not program. :) , I did one a few years ago and that was a 99 / T / V plate or so. Must be different with the Citroens then.

citronut wrote:Spider they dont have HT leads as they have a coil pack which sits right across all 4 spark plugs

regards malcolm
Must of mixed me up with another post Malcolm, I never mentioned the coil pack / leads. I figured it would be coilpack at that year though...
Andy.

91 205D-Turbo, gone but still missed
02 106D, TUD5B, gone but not really missed apart from the MPG
miked
Posts: 274
Joined: 16 Nov 2004, 21:26
Location: Up North, but not as far as Scotland.
My Cars: Xsara SX (2003) Last of the line.
x 6

Post by miked »

citronut wrote:Spider they dont have HT leads as they have a coil pack which sits right across all 4 spark plugs, also you should not use that old trick to test which plugs/cylinders are fireing, becaues if you create to biger spark gap you can damage the ignition module,

regards malcolm
But you can use the old trick of putting water on the outlet manifold next to the four outlets (when cold) then watching how quick each one dries after you start up.
wheeler
Posts: 6848
Joined: 21 Sep 2002, 19:07
Location: United Kingdom
My Cars:
x 717

Post by wheeler »

spider wrote:Well, I learned something new. The pug 106's can be re-coded as if you order a new key (inc the body) you simply recode it via the Diag... You do need all the keys though to do it as it will forget any you do not program. :) , I did one a few years ago and that was a 99 / T / V plate or so. Must be different with the Citroens then.
Thats different, you can code a new key (if you have the transponder code of the 2nd hand ECU). The way i read it i thought you meant re coding the 2nd hand ECU to accept the old keys.
Post Reply