Help Peugeot 406 ECU ignition problem

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Help Peugeot 406 ECU ignition problem

Postby ronw38 » Fri Sep 29, 2017 1:57 am

Hi from Rotorua New Zealand. A 2002 Peugeot 406 RFN engine with suspected ECU failure. The coil on time is way to long causing over saturation and ignition failure , all power-grounds and inputs checked out so opened the ECU for inspection it showed no obvious faults , cleaned the board reassembled the case and refitted ECU to carry on testing the motor fired up and ran perfectly [see attachment ] I assumed the flexing of the board while prying the bonded cover off had resulted in a cure !!! . It ran well for two weeks in and out of the shop and with plenty of road tests , during the last test it began misfiring and the original problem was back . Maybe some one has struck a similar failure ? I am told by a Peugeot tech that a donor ECU cannot be reprogrammed to another vehicle it requires a complete swap ECU BSI etc . Comments re the two issues could be helpful .
Attachments
Peugeot good ignition 3.psdata
(637.1 KiB) Downloaded 29 times
Peugeot faiied ignition 5.psdata
(2.61 MiB) Downloaded 29 times
Peugeot failing ignition 4.psdata
(758.54 KiB) Downloaded 28 times
ronw38
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Re: Help Peugeot 406 ECU ignition problem

Postby Liteace » Fri Sep 29, 2017 7:57 am

Whats the ecu make and number?
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Re: Help Peugeot 406 ECU ignition problem

Postby speck » Fri Sep 29, 2017 8:33 am

Looks like you have a coil driver problem.
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Re: Help Peugeot 406 ECU ignition problem

Postby ronw38 » Fri Sep 29, 2017 10:46 am

ECU Marelli Magneti will have to check correct name then I will include ECU number . The drivers are over loaded I think because of the directed on time , there are two drivers one for each pair of coils . I had an electronics wiz trace the trigger circuit back as close as he could get to the processor [ board unladen ] I then probed the trigger signal back to these points 10+ ms , processor you might conclude , but is this the output signal or the return signal for diagnostics ? I am sure the ECM is goosed . Fifteen year old Peugeot probably not many left over your way , even less here , Guys take a look give it some thought if someone has struck similar symptoms I would love to hear also , ECU compatibility Thanks for your responce
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Re: Help Peugeot 406 ECU ignition problem

Postby ronw38 » Fri Sep 29, 2017 11:13 am

Liteace wrote:Whats the ecu make and number?
Will get you that one Magneti Marelli SW9645123380
Last edited by ronw38 on Fri Sep 29, 2017 11:37 pm, edited 1 time in total.
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Re: Help Peugeot 406 ECU ignition problem

Postby ronw38 » Fri Sep 29, 2017 11:17 am

speck wrote:Looks like you have a coil driver problem.
Thanks I have posted a general reply on the forum
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Re: Help Peugeot 406 ECU ignition problem

Postby speck » Fri Sep 29, 2017 11:33 am

If you have a pulse generator you could trigger the coils.
that will tell you the state of your coil drivers.
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Re: Help Peugeot 406 ECU ignition problem

Postby Liteace » Fri Sep 29, 2017 3:41 pm

Just a thought, has this got the correct coil and plugs fitted, can't remember if it's the 2.0 rfn engine but one of the psa 2.0l engines does all sorts of strange s**t with wrong/cheap aftermarket coil and plugs
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Re: Help Peugeot 406 ECU ignition problem

Postby Tronic » Fri Sep 29, 2017 3:48 pm

Speck, it is not that easy because the drivers are inside the ECU, but if they where inside the coil pack it would have been an easy task, besides, problem itself lies unluckily, or most probably, in the ECU. Fact is, that can be seen in rising voltage (B+) and decreasing primary current, that the ECU try to limit the power dissipation for the driver to roughly 70 watts after about 7ms on time. However, the problem is that the charge time for the coil is far too long and of course the question you ask yourself: why... It would be very interesting if you could scope the gate drive so we can see how it looks like.

Guess most of the components on this board are SMD's which in turn make it a bit harder to see a bad joint to one of them. Probably no hair line cracks on these boards. A microscope in a situation like this is a very good friend :D

Liteace, I do not think it has to do with anything outside of the ECU because the engine worked just perfect after reassembling the ECU. Nasty fault...
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Re: Help Peugeot 406 ECU ignition problem

Postby ronw38 » Fri Sep 29, 2017 9:23 pm

Liteace wrote:Just a thought, has this got the correct coil and plugs fitted, can't remember if it's the 2.0 rfn engine but one of the psa 2.0l engines does all sorts of strange s**t with wrong/cheap aftermarket coil and plugs

ronw38 thanks I wired in a remote Ford coil pack early in the problem , with exactly the same result and patterns
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