Renault Megane Scenic 2001 1.9 dTi non starter - wiring problem

jonmid · Jul 15, 2014

I originally posted for advice about a month ago on the engines board, as my car wouldn't start after being left over the winter and I thought it was a problem with the engine.

With the great advice from some of the guys on here, I have now isolated the problem to the wiring, but unfortunately seem to have reached a dead end.

Was wondering if anyone over here can help?

I have a Renault Megane Scenic 2001 dTI with an F9Q744 engine.

It will not start at all normally, but if I remove the engine relay and bridge out terminals 3 and 5, it starts fine and will run. However, this leaves the other 2 terminals not connected. One has a permanent 12v feed and the other is a thin orange wire with no feed and I don't know where this goes to or what does.

Can anyone please tell me what this indicates and how to proceed to fix the car so that it will start normally again?

Would be really grateful for any help to get this car sorted.

Thanks

mickeybo · Jul 15, 2014

The main engine control relay 5 pin change over relay fitted with a internal diode between terminals 1 & 2. If you have a analog ohmmeter check between terminals 1 & 2 (diode) if the readings are switched either side and are the same then the diode is faulty.If I were you icertainly replace the relay

Lagdti · Jul 15, 2014

I suspect you'll find the wiring loom has corroded just below where it connects to the relay,the insulation may look fine but if you pull on them the insulation will break and the wiring will crumble.It sounds like it has lost its ignition feed,this is exactly what my old Laguna dTi did.

It might be worth trying a new/replacement relay,but I suspect the problem is more than likely in the loom.

mickeybo · Jul 16, 2014

Just a another check I would like you to do can you bridge out relay base terminals 3 & 2 ignition on or off & check if you have 12v's at ecu pin no 18. Can you check & post back Hth Regards Mickeybo

Renault Megane Scenic 2001 1.9 dTi non starter - wiring problem

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