Peugeot 306 Immobiliser problem

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JR
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Peugeot 306 Immobiliser problem

Post by JR »

Hi,
Today whilst driving over a speed hump, the engine suddenly cut out on my Peugeot 306. I had been driving for a while, so the engine was not cold.
On 'trying' to restart the engine I noticed that both the red and green lights on the immobliser keypad were illuminated. I tried re-entering the code, but there were no bleeps.
After about 10mins of trying, it suddenly accepted the code. Strangely though, the alarm indicator light continued to flash whilst driving, which obvicously only flashes when the car is locked
After about another 20 mins of driving, the car cut out again and both the red and green light were permanently illuminated again. This time it refused to accept the code and I had to call out the RAC.
Is it possible that I dislodged a cable when going over the speed
hump? Are there any obvious things I should check before contacting a garage?
Any help greatly appreciated.
cheers, JR
Dave Burns
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Post by Dave Burns »

Yes check the black four pin plug and socket on the injection pump, clean the contacts and if it looks necessary (and possible) squeeze the females in a bit[:I]
Might you have disturbed it some while playing around with the EGR valve, by the way leaving it blocked wont cause any problems for a diesel, as you have discovered they prefer it that way, it could be seen as anti social though since its there to reduce oxides of nitrogen.
Dave
JR
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Post by JR »

Hi,
I 'think' I have solved the problem, but do not understand why it happened...
To turn the flashing alarm light off, I turned the key in the ignition, whilst pressing the small square alarm button on the right hand side of the steering column. The indicators flashed quickly four times and the alarm indicator light turned off. (I didn't realise this, but the alarm indicator light is locatted to the left of radio and is separate from the flashing light on the keypad immobiliser).
I have never turned the alarm on before, as the keyfob was broken when I purchased the car and it is impossible to turn the alarm on without this. I just don’t understand why the alarm didn't sound and why the indicators didn't flash when the alarm went off. Also how was I able to drive the car for 20 mins with the alarm light flashing before it cut out?
I am a learning mechanic; could you explain where I would find the injection pump in relation to the oil dip stick plug?
cheers, JR
wheeler
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Post by wheeler »

if your car is fitted with an inertia switch it could be a problem with this,it is designed to cut of the fuel supply in the event of an accident/impact.if it is faulty then it might be triggering on less serious impacts (like going over a speed bump).also when this is triggered it brings on both keypad lights. if it is fitted to the car it's usually fitted on one of the strut mounting turrets,its a kind of square button with either a black or orange rubber cover.
rossnunn
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Post by rossnunn »

If there is no siren then this could be because there is a switch nder the bonnet which shuts it up! [:D] It sould accept your ignition key. It sounds like your factory alarm armed itself. by doing what you've done you have disabled it without the need for the fob. (It says how to in the manual).
Ross [:o)]
JR
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Post by JR »

I may have been haisty with my diagnosis as it did exactly the same thing today. Drove for around half an hour, parked for 10 mins, tried entering the immiboliser code and both red and green lights were illuminated.
According to the manual, this means the code has been entered incorrectly or there is a fault. I have neer changed the code, so it looks like there is fault 'somewhere'. As mentioned earlier, the problem orginal started when I went over a large speed hump and the engine cut out.
I can not see any obvious loose cable connections under the bonnet, but I am probably not looking in the right place. The model I owm is 95' 306XT auto. Does anyone know where the immboiliser is connected to in the enigine as I am sure there must a loose connection somewhere?
anny help greatly appreciated.
cheers, JR
CITMAN
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Post by CITMAN »

On my citroen zx which is also a 1995 model with a keypad immoboliser, which I assume is the same setup as your 306 has. The keypad is connected directly to the cars electronic control unit which I think on your model controls the fuel system and ignition side of things. I think you have fault within this system which is either connected to the keypad itself or the ecu or its wiring.
I would recommend that you get the ecu faults codes read. As to the cause I have no idea. And I wouldnt recommend messing around with the ecu as they are quite expensive if you break it.
But on the positive side it might be just a fault with alarm system which also has a separate ecu which is connected to the keypad, well it is on mine becuase if i pull the plug linked to the alarm horn the cars dies and doesnt start or do anything.
wheeler
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Post by wheeler »

citman - do you have a factory fit alarm ? usually the citroen/peugeot factory fit alarms & imobilisers are completely seperate,disconecting the plug from the siren should not stop the car starting.it sounds to me it's an aftermarket combined alarm/imobiliser as well as the keypad.
JR - did you have a look to see if you had an inertia switch ? faults like this rarely show up any fault codes,while both red & green lights are on its unlikely that the diagnostic machine would even get dialogue with it.also check the earth leads on the gearbox & body.
JR
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Post by JR »

Where would I find the inertia switch?
The problem I have is intermittent. This morning, it happily accepted the code, I drove for around 20 mins and the engine cut out, followed by both the red and green light being illuminate on immobiliser. I had to wait for around an hour before the lights turned out and jsut the red light was flashing as normal.
CITMAN
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Post by CITMAN »

Its got an aftermarket alarm which doesnt work. But I have been told by citroen specialist that the keypad is connected to the ecu. And has also been a subject in car mechanics magazine a few years ago. where they stated that if you lost the code for the keypad for some reason, it would mean a replacement ecu. Whether or not the keypad has a separate ecu I havent a clue but I doubt it.
Anyone no how these things work!!!!!!![:o)]
CITMAN
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Post by CITMAN »

doesnt the red and green lights lit up together indicate a fault[:o)]. ill have too look in my handbook and see what it says about this.
wheeler
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Post by wheeler »

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by JR</i>

Where would I find the inertia switch?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
see my first post on this topic.
citman - you are correct about the keypad being linked to the ECU,the piont i was making about the alarms & imobilisers being totaly seperate was that JR's starting problem is unlikely to be any thing to do with the alarm like he initially thought as is is a seperate system from the imobiliser.the keypad itself is a kind of ECU but like you thought its the injection ECU that is either locked or unlocked, both lights on do indicate a fault with the system but 9 times out of 10 it means the injection ECU is missing a feed or earth (i.e. the kepad cant comunicate with it so it brings both lights on) so if you try to read the fault codes when both lights are on the diagnostic machine will be unable to get dialogue with the ECU.
JR
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Post by JR »

Hi,
I have managed to solve the problem. At the back of the ECU, there is red plug which was slightly loose - I know an obvious thing to check, but the cable is well hidden.
Thanks for all you advice.
cheers, JR
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