 | Home > Technical > Puma Cuts Out – Why? |
 
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| Lorryman100 Member Since: 01 Oct 2010 Location: Here Posts: 2686  |
The 10AS unit doesn't stop the engine, the EMS does acting on information received from the 10AS unit. The passive immobiliser works by switching on the immobiliser after a set time once the key/fob is removed. It detects this by using the transceiver coil on the ignition barrel to detect the key/fob. If there is a problem with the passive immobiliser through a fault with the transceiver coil or fob then it will act as if the key is removed by initiating the immobiliser which will stop the engine by inhibiting the starter and fuel injector circuits. From the Puma workshop manual:  Click image to enlarge The pulsed feed from the 10AS module causes the magnetic field created by the transceiver coil to collapse and restore. The fluctuating magnetic field activates the fob (remote RF handset) to transmit a mobilization code to the 10AS module. The 10AS module receives the fob mobilization code via its antenna. This fob code is compared to a value in the 10AS memory. If the codes match, the 10AS module provides a mobilization signal to the instrument cluster. The instrument cluster acts as a gateway, converting the signal transmitted from the 10AS module into a signal that is recognizable by the ECM. So when the engine is running with a faulty passive immobiliser and it activates it will immobilise the engine by inhibiting the injectors causing the engine to stop. 
HTH Brian. |
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19th Oct 2011 11:32pm |
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| chrisbowler Member Since: 25 Jun 2011 Location: wales Posts: 101 |
Brian, I can see where your theory is coming from - so if we start the car and then disconnect the mag coil around the key barrel, then it cannot fault to failure.
We will try this today. Regards Chris |
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20th Oct 2011 6:31am |
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| Lorryman100 Member Since: 01 Oct 2010 Location: Here Posts: 2686 |
Chris, this isn't my theory as this is a common problem with Pumas experienced by a few owners on this forum (try a search) and others. The problems seem to always centre around the passive immobilizer in one way or another and it is usually sorted by disabling the passive immobilizer as the defender is still immobilized when arming with the key fob. When in warranty I would get the dealers to replace bits until they found the problem, but out of warranty as I said I would disable bits until it worked.
I am not saying this is Merlins issue but he has had issues in the past with the immobilizer (search) so in my view it would be the first thing to rule out before moving onto the other things I listed previously. Also you will need to do DDS learn (takes about 30 mins) if you swap over the ECU's or the defender will never start as the EMS will not be receiving a valid mobilization code as the EMS and 10AS wont be talking to each other. Brian. |
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20th Oct 2011 10:42am |
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| Merlin Member Since: 30 Oct 2010 Location: Newmarket Posts: 981 
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Good news, the Defender has been repaired! Seems that the Lucas AS10 immobiliser was at fault, as several of the terminals were corroded as the result of water damage. These have been cleaned and the fault has gone. It appears that the AS10 ‘pings’ the key fob and it wasn’t getting these signals back and hence was shutting down the engine, via the EMS. I imagine that the water has been creeping in from somewhere around the windscreen as I have had a pool in the foot well since new. The stealership has limited this flow but it’s still there.
I’d like to especially thank Lorryman100 for all the help he has given. He said that he thought it was an electrical problem from the start and that the AS10 was probably to blame. And it was! The garage in Llandovery, New Road Garage, were great although they had to go through a learning curve on the Puma engine. I would recommend them for repairs if you are in the area. They changed several bits that needed attention and hence I’m expecting a better performance now. Thanks to all who contributed to this thread. Merlin |
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24th Oct 2011 6:05pm |
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| Lorryman100 Member Since: 01 Oct 2010 Location: Here Posts: 2686 |
Glad you finally got the defender back on the road
Hope it didn't lighten your wallet too much..... 
Brian. |
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25th Oct 2011 3:22pm |
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| Merlin Member Since: 30 Oct 2010 Location: Newmarket Posts: 981
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Cheaper than buying a new car!
Thanks again, Merlin |
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25th Oct 2011 3:42pm |
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| Landscope Member Since: 23 Nov 2013 Location: Cumbernauld Posts: 8
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Hi All I have a very similar problem in my 2008 130 that I just purchaced.
Picked it up and drove it 65 miles of the 180 to get home and it started cutting out about every mile.... joined the aa at the roadside they checked it and wanted to recover it the 120 miles home for more money...... managed to nurse it home by coasting along hard shoulder when it cut out!! got it into my local independent specialist who have changed two different fuel valves (£130 and £150 parts so far)and its not much better!! So far its cost £500 in garage fees and £150 in aa membership!! now the garage want to put a fuel pump on it to see if that makes it better!!! any ideas or help Please!! Thanks Brian |
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23rd Nov 2013 2:06pm |
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| Lorryman100 Member Since: 01 Oct 2010 Location: Here Posts: 2686 |
@Landscope, if you want you can drop me your email address as I am not that far from you, about 30mins.
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23rd Nov 2013 3:13pm |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558 
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I tried the theory of as10 unit checking the key every 5 mins as stated somewhere on forum .. started mine in usual way key fob on key ring as normal left it running then took fob off took it with me and went in doors about 50m away had cup of tea (left it running ) waited 25mins went out still running fine so that's that theory out the window ... I only checked this as I know that alarm unit are not allowed to cut engine once running
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23rd Nov 2013 4:28pm |
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| Lorryman100 Member Since: 01 Oct 2010 Location: Here Posts: 2686 |
@munch90. Post up or pm me your 10AS settings page please and I can then tell you the reason why that happened.
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23rd Nov 2013 5:39pm |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558
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All settings must be standard nothing ever been changed . Not sure if this helps
when i went out to car was still running ok with fob indoors ,turned off key left it 30 secs then tried to start ran for 1-2 secs then cut out . and ive worked on cars for years with basically the same units and they have always been like this .. when ever I suspected a engine ecu non starting problem fault I would then plug a s/h ecu (non coded) in knowing that if it was a ecu problem causing the non start it would run for 1-2 secs then cut out .. if it started and fixed the problem then recode ecu to as unit to run as normal |
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23rd Nov 2013 6:14pm |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558
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I have never known a immobiliser fault to cut engine once it is running and that's on any car any make ..yes many non starting issues .. mainly not recognising key or fob chip
as far as I know immobilisers are not allowed to be wired or programmed to cut engine when already running Corroded wiring cutting engine out that's a wiring fault not a unit fault in my way of looking at things if a starter wire corrodes and falls off that's not a starter motor fault its a wiring fault ? This is taken from vosa vehicle approval manual Anti thief immobiliser It must have a Actuation Which is a distinct and separate Fuction From stopping the engine I think that means a immobiliser is allowed to stop it from starting not stop the engine |
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23rd Nov 2013 6:52pm |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558
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Off topic but may be of use to someone
You are not allowed to remotely stop a car once it it is moving ie stolen .. Your only allowed to immobilise once it has stopped and turned off to not start again .. You can get tracker kits to do this but even then only control centre can do it not the owner Imagine the accident you could cause if we could do it !!!! Last edited by munch90 on 23rd Nov 2013 7:34pm. Edited 1 time in total |
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23rd Nov 2013 7:33pm |
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| Lorryman100 Member Since: 01 Oct 2010 Location: Here Posts: 2686 |
Not disagreeing with you or arguing about your own experiences on anything you have posted munch90.
All I know is that I have have disabled and played about with different settings on the 10AS on my Puma and know what the 10AS is doing for whatever parameters are set within the settings page, and armed with this info was the only reason I had an idea as to the op's (Merlin) problem with the engine cutting out as I had previously tested several scenarios using my IDS and my MSV2 diagnostic tools first. Maybe a lucky guess on my part, could easily have been, but as far as I am concerned the problem was identified and fixed, after all Merlins engine was cutting out whilst driving, albeit caused by a conectivity fault, but we all got to learn from the process, which apparantly cannot happen as there are protocols in place to stop this happening yet it can happen if certain parameters are met  , which is what this forum is for in helping with the out of the ordinary faults. JMTW |
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23rd Nov 2013 7:33pm |
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