engine light on after New map sensor & stepper motor fitted

[lakemaligne]

Hi all,I have owned from new a 1996 2ltr petrol 406LX which has covered 139,000 miles,which has never had its engine fault light come on,until now.In February my car developed a sharp jolt as the power came in and out ,when ever I lifted my foot on and off the throttle.The tickover would remain at 1200 rpm if I engaged neutral while still moving along,only dropping to the normal 950 rpm once the car had come to a halt.During this time there was no engine fault light.So my dealer replaced the stepper motor,then the map sensor,then the oxygen sensor ,and finally the throttle potentiometer(TP) ,one at a time in order to cure the fault.As soon as they had replaced the stepper motor and map sensor ,the fault light started coming on twice a day,which recorded "irregular fuel delivery" on the diags.It was only once they had replaced the TP that the jolt dissappeared and the tickover behaved itself,but still the fault light kept coming on despite having reset the "Autoadaptives" several times.The car is now driving perfect again except for this re-occuring fault light.I have had 2 dealers look at the car and one suggested it might be the new map sensor playing up.They also gave me some "Wurth-SeBesto" petrol additive to clean the injectors to see if that cured the problem,but it has not.Can anybody out there tplease ell me what has caused the light to come on and whether it is something I should be concerned about as the car is driving very well.

[Welly]

Unfortunately you could go about replacing all kinds of stuff at great cost but why bother if the car is driving well otherwise?

You've obviously cared well for the car in all these years and it's nice to have everything working 100% but maybe you'll have to wait until some problem manifests itself more clearly?

It's a shame James is not around at the moment as he knows your engine inside out!

It would be worth noting that a couple of our members have run the 2.0 petrol up to nearly 200,000 miles and by all accounts it's one of the most reliable and simple engines Peugeot ever made, heck one member even ran his for 40,000 miles on the same oil - but of course I wouldn't want to name and shame him here

[mjb]

one member even ran his for 40,000 miles on the same oil - but of course I wouldn't want to name and shame him here

Pfft I'm sure it was more like 60,000... plus whatever was on the car since its last service when i bought it

[Welly]

Ooh there you are

How you doing fella?

[mjb]

How you doing fella?

I'm good, the car though... hmmm

Couple of days overdue for its MOT which I've got booked for tomorrow morning and I'm not sure it's going to pass. I can't pin the noise down, but I'm sure the egg sauce is blowing by the centre box, possibly the rear joint to the pipe, and I've still got that grinding noise from the nsr wheel (which hopefully the examiner won't actually be able to hear)

It only sounds like a tiny egg sauce hole (I noticed it was a bit noisier, but thought 'nah' until I got my head under while contorting my leg to jab the throttle), but it's VERY warm at the side of the car when I get out

We shall see. Only thing is I can't afford a new exhaust system this month, and I've got to drive down to Farnborough this weekend. GAH!

[Welly]

You should be ok - the 406 is not a big let down come MOT time really. If you haven't got the Nazi MOT tester from hell he might not even bother with the egg sauce too much.

Farnborough Air Show eh? I went to RAF Waddington on 6th July and it was great. The RAF Typhoon was awsome they also did a ghey attempt at launching the Vulcan into the air but it had "electrical issues" (French? )

They've been doing the Vulcan up at Bruntingthorpe (about 10 min from my house) and no f**ker said a dicky bird (the locals don't want too many vistors I reckon)

It flew over my Lad's school before the show and everyone nearly shat themselves

[teamster1975]

How you doing fella?

I'm good, the car though... hmmm

Couple of days overdue for its MOT which I've got booked for tomorrow morning and I'm not sure it's going to pass. I can't pin the noise down, but I'm sure the egg sauce is blowing by the centre box, possibly the rear joint to the pipe, and I've still got that grinding noise from the nsr wheel (which hopefully the examiner won't actually be able to hear)

It only sounds like a tiny egg sauce hole (I noticed it was a bit noisier, but thought 'nah' until I got my head under while contorting my leg to jab the throttle), but it's VERY warm at the side of the car when I get out

We shall see. Only thing is I can't afford a new exhaust system this month, and I've got to drive down to Farnborough this weekend. GAH!

I'm in the same boat Matt, MOT on Friday. I'm 99% certain the head gasket has blown and I've got that f*cking knocking noise to track down and cure
You're gonna be right in my neck of the woods at the weekend! I was watching a pair of F15's flying by earlier!
If you happen to come across a throttle linkage in your box of bits pop by and I'll put the kettle on

[mjb]

Haha yeah I was supposed to be at RIAT down at RAF Fairford last weekend, but they cancelled it. Judging by the amount of water on the fields I'm actually glad I didn't have to drive my car into it (and subsequently be dragged out by a tractor)! I've got to see the Vulcan again though - I saw one at RAF Cosford when I was a little kid and remember about a minute after it had gone past the noise level dropped and all you could hear was car alarms

Teamy: If I find it I'll bring it down, but tbh it's not looking good sorry

[teamster1975]

It's alright, I was teasing
You're very welcome to pop in for a cuppa anyway, I'm putting laminate flooring down in the lounge so the tea will be flowing!

[Welly]

I reckon we've well and truely knackered this guy's thread now

[mjb]

Sorry


For the OP:
Unplug the ECU for 10 minutes to reset/clear it, drive around until the fault comes back, then take it to a garage/dealer who can read the fault codes from the ECU. Don't let them replace anything; it's probably just a dirty connector on one of the newly replaced parts. Try getting a can of electrical contact cleaner speay from Maplins and have a go at them

[Welly]

It's the round shaped thing behind the air box with a wire going straight to your foot!

Mines thrown the ECU light up about 4 times now. I have an old dealer invoice for £47.00 from the last keeper.