Mend > Cars

Over revving Peugeot 406 1998 1.8 Petrol engine?

I have seen a thread on here with an almost identical problem to mine. When i start the car it appears to be idling just fine at about 1300 revs (ok when cold ) . The problem is that within minutes of driving (i.e when engine is getting warm) once i go into neutral at a roundabout/junction/in traffic it is as though the engine has a mind of its own. the revs shoot up to anywhere between 2000 and 3200 (generally nearer the upper limit) and it continues to rev up and down without me touching the accelerator. It drives absolutely fine otherwise, once i'm in gear it is not loosing power or jerking through the gears. I have replaced the stepper motor (idle control valve) , removed and cleaned out the throttle body with carb cleaner and replaced the engine management coolant temperature sensor. Had a diagnostic done at Peugeot they said no fault was shown and recommended new stepper motor which a mechanic friend of mine has done. I've also tried (as suggested on another thread) resyncronising by turning ignition on 3 times for ten seconds but this hasn't changed anything at all. Please help !!!

Greg Brown
March 2009

Peugeot Peugeot 406 Vehicles, Cars Over 1998 Petrol

I have a 2.0 litre 406. Mine suffered what sounds like a very similar fault. Peugeot dealership found all sorts of expensive reasons but none of them fixed the problem. A private mechanic found a small crack in an air inlet pipe which meant the control mgt system could not regulate the fuel/air mix causing the reving.

STS
May 2012

I had exactly the same problem today. The AA said it was the throttle body. My local garage removed it, stripped it and cleaned it for £70. Now, it's fine.

PR
May 2009

Thanks for that, i have had a diagnostic done already but prior to the new idle control valve being fitted. Are you saying you have to have another diagnostic in order to get the ICV to resyncronise. Trouble is i don't trust pEUGEOT WHO WANTED OVER £200 to fit a new ICV which my mate fitted in 5 minutes (cost me £40 for the part). If a diagnostic is guaranteed to work i'd do it but the car can't be worth more than £250 so i don't want to keep chucking money at it if you see what i mean ?

Greg
March 2009

may be worth trying a manifold pressure sensor located on the underside of throttle body failing that it maybe wiring fault or engine ecu fault the resyncronisation of the idle regulation motor needs doing on diagnostic equipment

pmt
March 2009