Engine Management Light Staying On

[W111ALG]

Hi guys,

My engine management light came on yesterday in my 172 Cup. I had been working under the offside wheelarch where the horns are as I had a wee bit of problem with my horn not sounding to good. When I started the car the Engine management light had came on and has stayed on. I don't believed there is anything I could have bumped near the horn which could have brought it on.

The spark plugs/coilpack and downstream lambda were all replaced at the end of last year. I have checked and I am getting a good spark in each cylinder ok. The car also had an emissions test in January and the CAT and front Lambda were reading ok. The car seems to be driving fine, coming on cam ok, starting and idling fine(Well for a 16V Renault engine anyway!)

Theh only problem I have had with theb car recently is the De-phaser pulley has started to make a slight noise when VVT is actuating at 1800rpm. I am getting a voltage at the solenoid ok so have just bought a new de-phaser and cambelt kit to change shortly. I don't believe the De-phaser would cause the engine management light to come on though.

Anyone have any other ideas? I have also tried the old disconnect the battery for an hour trick. Is there something in the ECU that this will 'clear' after so many drive cycles?

Cheers,
Will

 

[Tom@JMS]

It turns off after a distance driven - off the top of my head I think it is 200 miles.

mines comes on every couple of weeks dues to a faulty rear lamba that isn't even doing anything (decatted - so wrapped in tape and tied up under the car.) It did this before and after decatting. I had it on diagnostics and it reads nothing just occasionally 'detects' a fake reading and triggers the warning light, no harm done, just ignore it.

If the car is running poorly when it comes on then it is worth getting it looked into as it could be the carbon canister as that is in the nearside wheel arch & I believe it has a lamba/sensor of some sort in it.

 

[W111ALG]

Is there a simple way I can disconnect the Carbon Cannister to test?

 

[Tom@JMS]

mmm search on here for carbon canister, you can take them out although I don't think it is a good idea personally.

Just my 2 pence worth, let me know what you find out. The simplest way to do it will be to plug it into a diagnostics and see what the fault code is tbh.

 

[W111ALG]

Gonna buy a code reader, cheaper than having to keep putting it in to get faults diagnosed when there problems.

 

[Tom@JMS]

could have done it for you for £15, shame your so far away!

 

[W111ALG]

Got a code reader off ebay for a few quid more than £15, handy bit of kit, really easy to use.

Turns out its the pre-cat Lambda. Doesn't seem to be any air leaks in the exhaust from what I can see so will swop out the pre and post lambda probes and see if it makes a difference.

 

[W111ALG]

In case anybodies interested this is the Code Reader I got:-

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=300301790833