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Renault Megane 1.6 1998 - Non start, immobiliser problem - Fixed #

Posted by Pete Mutlow on October 31, 2011, 7:01 pm

Year of Manufacture *: 1998
Engine Size and Code *: 1600cc
( Optional ) ECU Type: Fenix 5
( Optional ) Scanner Used: ACR4 G2
( Optional) Fault Codes: Nil

Evening,

Would appreciate some thoughts on this. This vehicle was bought by a garage as a non-starter due to an immo problem. ECU has now been modified as free-run and I note that the pin which goes to the immo box has been removed. With ignition on, the EML fails to illuminate and I cannot get any comms from the ECU. Also, I cannot hear the fuel pump prime nor hear any relays click. However, if I bridge the control relay then I can hear the fuel run in the engine bay.

I have voltage at the coils on the LT circuit but no HT. I do not get voltage at the injectors unless I bridge the control relay but no switching and no fuel. I have checked the engine earth strap at the back of the engine which appears to be a common fault. Checked all relevant fuses and found nothing untoward. At one stage the vehicle somehow operated the central locking with the keys in the ignition. Not sure if that is connected.

Nearly forgot to mention. I have scoped the crank sensor and can see a 1v waveform.

Normally, I would say that this is an ECU problem. However, this is the second ECU tried. The first ECU had obviously been doctored because the "mastic"? at the back had been carefully scoured out and the pin to the immo box removed. The second ECU has just had the pin removed.

So there it hangs. Have I missed something or is there something else to check? Or is an ECU problem? I would be grateful for your thoughts.

Regards

Pete M

Re: Renault Megane - Non Start

Posted by Michael Whitworth <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5568' width='330' height='300' border=0 style='border:none;'> on October 31, 2011, 7:48 pm, in reply to "Renault Megane - Non Start"
Mike Whitworth - Administrator

Hi pete,

I know you say you have checked Engine/Gearbox earth and relevant fuses, but have you actually checked All Engine ECU feeds and earths?

Mike

M.O.M. Miserable Old Manc

Re: Renault Megane - Non Start

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on October 31, 2011, 9:26 pm, in reply to "Re: Renault Megane - Non Start"
Peter Mutlow

Thanks Mike,

Yes I have checked the ECU feeds and earths. However, in light of your suggestion, I re-checked the AD info and whilst I remember I had battery and ignition supply, I can only remember checking one of the 3 earths. I may be mistaken on this point and will re-check again in a couple of days.

Regards
Pete M

Re: Renault Megane - Non Start

Posted by James McCallum <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat5583' width='330' height='300' border=0 style='border:none;'> on November 1, 2011, 10:10 pm, in reply to "Re: Renault Megane - Non Start"
James McCallum

Hi Pete, is there an Inertia switch have you checked it? Wiring I have shows main relay fed by inertia switch, coils are fed before inertia and injectors after.
HTH
Jim

Re: Renault Megane - Non Start

Posted by Peter Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on November 2, 2011, 9:58 pm, in reply to "Re: Renault Megane - Non Start"
Peter Mutlow

Evening All,

Thanks James. I assumed the inertia switch was ok because I was getting ignition on battery voltage at the relay. Checked it anyway and have battery volts on both sides of the switch.

Michael. Checked all ECU feeds (2) and earths (3) and all intact. The only odd thing I encountered was that one feed (ignition off) took a while to get to battery voltage...maybe 10 secs. Starts off at about 9v and achieves NEAR to battery volts in that time. No idea why that is.

Anyway, today I took a close look at the control relay and think I have found a problem. Disregarding pins 87a and 87b I took readings at the relay SOCKET and this is what I found. Pins 85 and 86 had battery voltage with ignition on. Pin 30 contained direct battery voltage. According to my old notes, I should have one pin with an earth (pin 85). If that is the case, why do I have battery voltage? I can check if this is coming from the ECU, or a break in the harness somewhere, cross feeding the battery voltage.

So before I revisit and spend another few hours on this thing, I would appreciates your thoughts on my findings/comments.

Regards

Pete M

Re: Renault Megane - Non Start

Posted by james mccallum <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat5583' width='330' height='300' border=0 style='border:none;'> on November 2, 2011, 10:38 pm, in reply to "Re: Renault Megane - Non Start"
James McCallum

Hi Pete, you could connect relay and do volt drop at pin 40 at ecm, according to autodata its pin 40. Ign off it should be supply voltage, ignition on it should be 0 v. Sounds like relayplate.
Jim

Re: Renault Megane - Non Start

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on November 2, 2011, 11:37 pm, in reply to "Re: Renault Megane - Non Start"
Peter Mutlow

Thanks for that James. It seems that my Autodata disk is confused on this. It shows pin 40 as IAC valve or control relay depending where you look. This is confirmed in the wiring diagram as IAC valve. It also shows that the control relay is connected to the ECM at pins 48 and 52. Maybe my CD3 is incorrect. Anyhow, if pin 40 is correct, and the voltages are not as you say, are we saying that the fault lies in the relay plate?

Regards

Pete M

Re: Renault Megane - Non Start

Posted by james mccallum <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat5583' width='330' height='300' border=0 style='border:none;'> on November 3, 2011, 6:09 am, in reply to "Re: Renault Megane - Non Start"
James McCallum

I will see if a colleague of mine has the renault diagram official!! The volt drop will confirm if the relay plate has poor connections, as you suspected. Best option is to follow wiring colour to ecu, relay and connect test probs to the relay pin 85 connection, AT THE ECU, when operated, the relay should use all the voltage, your basically checking the earth line. If less than o.2 volts, use fly leads to connect relay to relay plate and do same things at pin 85 at relay. Supply voltage when relay is not operated, If voltage is high >0.2 volts, there then high resistance in relay plate after relay but before ECU earth point.
I think my autodata is older than yours, hence wiring difference.
HTH Jim

Re: Renault Megane - Non Start

Posted by Lee Mackintosh <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1348' width='330' height='300' border=0 style='border:none;'> on November 3, 2011, 8:24 am, in reply to "Re: Renault Megane - Non Start"
Lee Mackintosh

I also have pin 48 as the fuel pump relay switched earth side from ecu.

Re: Renault Megane - Non Start

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on November 3, 2011, 9:45 am, in reply to "Re: Renault Megane - Non Start"
Peter Mutlow

Morning all,

Thanks James and Lee. I have checked a more up to date version of AD which shows pin 48 as the switched earth side from the ECU.

This, like my version, also shows relay pin 87b feeding the injectors and also connecting the ECU at pin 52. I have made the assumption that pin 52 is where the injectors are switched.

So to cut to the chase, if I can successfully bridge the relay, without having to rely on pin 48, why is not pin 52 switching the injectors? In addition, why is there no spark from the coils which has 12v either side of the LT circuit and does not rely on the control relay? My brain hurts

Regards

Pete M

Re: Renault Megane 1.6 1998 - Non start, immobiliser problem #

Posted by james mccallum <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat5583' width='330' height='300' border=0 style='border:none;'> on November 3, 2011, 9:51 pm, in reply to "Renault Megane 1.6 1998 - Non start, immobiliser problem #"
James McCallum

Hi Pete, is it worth scoping or cleaning or replacing the crank sensor. I have just done rank sensor on a similar model. I have been told it is very common.
HTH Jim

Re: Renault Megane 1.6 1998 - Non start, immobiliser problem #

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on November 3, 2011, 10:18 pm, in reply to "Re: Renault Megane 1.6 1998 - Non start, immobiliser problem #"
Peter Mutlow

Thanks Jim already tried that. I scoped the crank sensor and although the trace itself was good, the voltage was a bit below par at about 3/4 volt. So replaced it just to make sure. Another part adorns my van but fortunately I use a fair few of these.

Regards

Pete M

Re: Renault Megane 1.6 1998 - Non start, immobiliser problem #

Posted by james McCallum <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=ukat5583' width='330' height='300' border=0 style='border:none;'> on November 4, 2011, 9:22 am, in reply to "Re: Renault Megane 1.6 1998 - Non start, immobiliser problem #"
James McCallum

Hi Pete, have you checked crank sensor signal at ECU? Is the voltage supply and earths all present at ECU? Is the immobiliser definately removed?
HTH
Jim

Re: Renault Megane 1.6 1998 - Non start, immobiliser problem #

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on November 4, 2011, 8:52 pm, in reply to "Re: Renault Megane 1.6 1998 - Non start, immobiliser problem #"
Peter Mutlow

Well, I sent in my auto-electrician man this morning and it transpires that the ECU is either faulty or the immo is still active. So it appears that the garage has had their trousers pulled down on this one. Been a bit of a waste of my time then....oh well, swings and roundabouts. Glad to see the back of it nonetheless.

Many thanks once again for all your contributions.

Regards

Pete M

Fixed #

Posted by Pete Mutlow on January 18, 2012, 6:18 pm, in reply to "Re: Renault Megane 1.6 1998 - Non start, immobiliser problem #"
Message modified by board administrator January 20, 2012, 9:23 am

Evening all,

Had to go back to the garage to attend to another vehicle and was told that they fitted another free-run ECU to this car and it started and ran fine. Glad to see the back of it with a good result.

Thanks all for your interest and inputs.

Regards

Pete M

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