A6 immobiliser problem

[NEBAM]

Hi All,

Looking for advice with an Immobiliser problem i think!

Have an Audi A6 2.0se petrol 1996 saloon model

Car will start okay sometimes and drives fine, but other times will only turn over and nothing!

If i lock and unlock it will start again sometimes, wouldnt start yesterday at all so just left it didnt lock it etc went today started straight away stopped it and wont start again!:mad:

Think this seems like immobiliser problem, key fob works fine locks car opens car pressed again and indicators flash, have tryed plugging fob into the part below steering wheel indicators flash but makes no difference to starting!

Have checked wires back ignition seem okay!

Heard there is a immobiliser relay but dont know which one it is, there is a row of 5 relays? below the steering wheel!

Advice most welcome! or is there a way i can switch immobiliser off? have diagnostic machine but doesnt do OBD1 system and no obvious warning lights on anyways!

I appreciate you might want to pm me if there is a way of switching off rather than post on forum! Im not a new member previously had A4 when joined 2 years ago. thanks in advance

[kenney]

This is not an immo fault,but you do need a fault code read

[NEBAM]

Hi Kenny, thanks for the reply! will see if i can get hold of a OBD1 system! but would have thought there would be a light on for a fault code!? can i ask why you think its not a immo fault? many thanks

[kenney]

with a factory fitted immo,the engine will start and stop after a few seconds if there is a fault

[NEBAM]

hi thanks for that Kenny,

have just tryed something else as a friend had asked if i tryed bumping / towing when it wont start!

So got car started of the key again :aargh4: for some strange reason, so took it a drive free wheeling along the road towords my house switched it off tryed starting with key just turned over didnt start so put it in gear and bumped okay! dont know if it was a coincidence or not as when i stopped it at home it started of the key again and again and again lol

just wondered if this is the case that it will bump start if anybody might know the problem? thanks

[kenney]

I think maybe you have a faulty ignition switch

[NEBAM]

Intresting Kenny, can you be more pacific, i take it you mean the connection plug at the rear and not the barrel part? also if you dont think it has anything to do with the immobiliser then what would be failing? as obviously the power is getting to the starter so not sure what would be failing then? many thanks

[Crasher]

I think Kenny is more Atlantic, I agree with his idea about the ignition switch.

[kenney]

It is possibly the electrical part of the ignition switch,when in the (50) position (starter position) looses contact with the (15) position power to the ignition

[NEBAM]

UPDATE.

Have checked wires at rear of ignition barrel and everything seems fine,

Car wouldnt start today so got it towed and started straight away, drove it 50 yds home switched it off and started straight away of the key!? still starting of the key tonight??

i am now wondering could this be a fuel problem?? maybe dodgy filter etc any ideas??

Was thinking if its a wire in ignition how would towing it make it suddenly start of the key? many thanks

[kenney]

You may have checked the wires,but did you check the output on the 15 contact on the switch.I dont think it is fuel related.

[NEBAM]

Hi Kenny, no never checked outputs but will do!, is it just to show a live feed? 12 - 13v ? when turninig over? do you know the colour of this wire? thanks

[Peter D]

It will not be a dodgy filter. What this could be is that in the igniton on postion there is a 12v feed to the engime management ststem but when you are in the cranking position this feed is failing so when you let go of the key the feed returns but the engine has stopped cranking. This is why iyf you bump start it it works. You need to check this by identifying the ignition connection and when it does not start use a meter ti if the ffed is correct. Depending on your engine code you may have a faultly cam shaft sensor which, with a low signal will inhibit anf spark or fuel. Bump starting it turn the engine over a lot faster and the signal may he high enough to enable it to start. Regards Peter

[Peter D]

If this is an ABK engine then you may have a faulty hall effect sensor G40 in the distributor. What is you engine code. Regards Peter

[kenney]

Black terminal 15

[NEBAM]

Thanks Kenny,

Peter the engine code is ABK.

[NEBAM]

Peter the engine code is ABK. i tryed to give it a clean with Contact Cleaner made no difference! is there a way of checking the sensor with a volt meter at the plug point at the distributor? thanks

[Peter D]

PM me your email address or post it in this thread. Regards Peter

[NEBAM]

Have sent you PM Peter, thanks

[NEBAM]

hi Peter, getting a voltage reading from pins 1 and 3 hall sensor 18.7v with ignition on, tryed pin 2 through meter and was pulsing up and down from 340 to 460 ish when turning over. not sure what it should be? can check fuel pump tomorrow as lot of things in the boot of car and starting to get darkish here! do you know what readings should come via pin 2 at hall sensor? many thanks Gary

[NEBAM]

It is only a narrow pulse to the meter will not measure a lot but it seems the sensor is working. Have you memved a plug and tested for a spark.

You do not need to go into boot. Unless you are trying to hear the pump You can if you have a current range of 10 amps just probe across the empty F17 and see the pump drawing current.

Just checked these out and getting a spark (but also add the plugs were well black suited up and were previously cleaned 2 weeks ago) checked the connection over fuse 17 and getting a initial reading for 2 seconds with ignition turned on then getting higher constant reading when turning over! regards Gary

[Peter D]

Good it is not the immobiliser or the Dizzy. Did you check you could hear the pump running or did you measure the current it was drawing. Were the plugs wet. Is it a good healthy blue crack of a spark. Buy yourself a can of quick start we may need it. Remove the plugs clean and put them in the oven for 10 mins at 150 degrees. Spin the engine over to let some air through the pots and try again, a squirt of quickstart may assist you if you have a helper. Regards Peter

[NEBAM]

HI, I measured between the fuse 17 for the current, fuel pump also makes a noise for a few seconds when ignition turned on, plugs were totaly dry and black sooted up, hard to tell about spark as was doing it myself turning over and trying to view but there is a spark there, will try the oven with the plugs idea, as for easy start makes no difference previously tryed! sometimes engine will try and start sometimes nothing, spraying in through air intake pipe.

Car allways starts with a push though!

When the car ignition is working (IE it starts of the key) it starts first turn of the key, it doesnt turn over for ages and not start it just starts straight away! as when if i bump start it then switch it off it will start of the key first turn sometimes for days after it then again it fails again,

I noticed sometimes (rarely though) if i lock and open the car several times with the fob it will start of the key but not allways! or if i just leave it a few days unlocked and try it will start of the key!

this really has me beat!!

[kenney]

Fit a simple temporary switch between the B+ and ignition 15,when the fault occurrs throw the switch and see if it helps

[Peter D]

Kenney's on the money with a temp switch but a spark and no fuel does not add up unless the fuel pump relay or pump is playing up. As the bump start works it does sounds like the ingigtion switch is the problem. Regards Peter

[NEBAM]

Kenny / Peter, is there a easy way to get at the ignition switch? i have only checked it from underneath best i can by removing the bottom landing panel!, is there another way of accessing like maybe remove the clocks? or another panel?

Also this temp switch when fitted do i just use it to start the car and switch the switch back of or can i leave the power on all the time? thanks

[kenney]

The ignition switch can be replaced from under the dash 2 screws.The temporary switch is only to help diagnose the problem,it should be normally off,and when the problem occurrs,throw the switch,and see if the engine then starts.

[NEBAM]

Fit a simple temporary switch between the B+ and ignition 15,when the fault occurrs throw the switch and see if it helps
Have done this, connected wire to ignition 15 and another wire to ignition B (its Blue) and fitted them to a switch, tryed turning over with switch on but made no difference! ?

[kenney]

From the battery + -----switch-------- ignition 15 you can use the (15 position on the coil)

[NEBAM]

Hi Kenny, think i got confused then!

So to clarify i have to take a live feed from the battery (etc) to a switch then from switch to ignition wire 15 (which is a thick black wire) ? regards

[kenney]

Correct

[NEBAM]

bloody car lol, before i could try the switch it started first turn! and keeps starting but ive not done anything !?

even after i had the ignition plug of attatched the wire put back together wouldnt start. did notice i thing different that when it started i got a warning light for the temp flashing red!? stopped it and waited a min started again and light out! maybe just the battery getting low and spiked it!??

So will have to wait until it wont start again to try the switch idea.!

[NEBAM]

From the battery + -----switch-------- ignition 15 you can use the (15 position on the coil)
Hi , right have worked out the meter crash course lol, it is showing 4.32 amps when fuse 17 is removed and turning engine over! car wouldnt start today so tryed that wire live from battery to switch to point 15 on ignition no difference though still wouldnt start!

Further to this i tryed something else, even though the engine was turning over okay i put a battery charger / jump / booster on it (just to save the battery from getting low) waited 10 mins and started no problem!

So is it possible that even though the battery is turning the engine over okay that it is not producing enough ampage to run sensors fuel pump etc? or is this just to simple lol, and it maybe make sense as to why it will bump okay!?

[kenney]

I fancy that is just a coincidence that the engine started after you boosted the battery.You say the engine is turning over okay,and you would most certainly hear, what is called a lazy starter.I think maybe it is time you had a fault code read.Do you know how to measure the resistance of the coolant sensor

[NEBAM]

Hi Kenny, starter motor fine turns over okay! as for coolant sensor no idea but willing to give it a bash if you can explain, my meter does do temp readings as well! car has started all day with charger on so will leave overnight again and see if it starts without it then attatch it if it doesnt to see as well no harm in trying that.

[kenney]

Unplug connector at coolant temperature sender.
Connect up multimeter for resistance measurement between contacts 1 and 2 at sender.
30 °C corresponds to a resistance of 1500...2000 ω

[Peter D]

What voltage do you have when cranking. I can not recall if yours has a voltage meter in the dash. 10 to 10.5 should be OK but below that there may be an issue.
Kenney has a good call with a potential faulty temp sensor so the choke does not kick in, but they normally fail high res which demands choke. Regards Peter

[NEBAM]

OK will give it a check in the morning and let you know Kenny cheers

[NEBAM]

What voltage do you have when cranking. I can not recall if yours has a voltage meter in the dash. 10 to 10.5 should be OK but below that there may be an issue.
Kenney has a good call with a potential faulty temp sensor so the choke does not kick in, but they normally fail high res which demands choke. Regards Peter
I cant remember of hand what the dial says (does have one though) do remember when running it sits about 14 volts !

The battery on the car was fully charged at 5.00 tonight, just put the charger back on the now (unplugged) to check the reading (has 5 lights on charger system) and it is down to 2 lights now so either the battery not holding the charge (maybe dead cell) or something on the car draining it !

I have bought a second hand battery and have it on charge the now to see if that makes any difference tomorrow.

[NEBAM]

Hi, well tryed to start the car Saturday no joy! put the charger on it and started first turn!, so changed the Battery and it seems to be starting no problems now! everyday first turn! so hope it was just a battery problem time will tell!

now next thing while im on! my plugs seem to be getting really sooty in the matter of days with just starting it! any advice what the cause is?

7957

clicking the pictures seems to make it larger!

[kenney]

If the engine has not come up to normal operating temperature the plugs will not have had a chance burn clean

[NEBAM]

Hi, just a wee update!, car is starting no problems now after the battery change! so looks like it wasnt enough horses from the battery even though it was turning over okay! also plugs are fine now at operating temp ! thanks you guys for all the advice and help and thanks to the forum for being here lol cheers