mart94wrx

Also tried unsuccessfully in Electrical. What is the dashboard warning light to the left of the oil warning light. Two horizontally curved lines, with wavy lines coming vertically out of the top (lit up red with other warning lights, fails to extinguish when engine running. Need an answer tonight asap. Cheers,

Mart.

RRH

'cat on fire'

have you decatted the car? its sensing a problem with the cat- which could be because it's not there. it's an emissions related thing- if you've de-catted unplug the sensor from the loom as it doesn't need it.

mart94wrx

One reply in Lighting/electrical - I've had the downpipe off, and it's been suggested that the Lamda sensor could cause this light to come on. If so, the plug connection was awkward to get back together, so I reckon that this is the cause - any more thoughts on this?
Cheers,
Mart.

Dark Blue Mark

As RRh says, its definately the cat on fire sensor. I think this is what you've unplugged. On your car, the lambda sensor is under the front wing in the exhaust header. Cat on fire is in the downpipe. It wans of exxess temp in the cat.

MB

RRH

They don't usually light up when they're unplugged though, unless I am mis-understanding what you are saying?
Said sensor is redundant if you've de-catted, and I must admit I tend to disconnect anything that gives warning lights

Dark Blue Mark

Yep, if there's no sensor they dont give a reading to the ECU and no warning. Normally.

Did you put the original Dp back on and plug the sensor back in?

MB

mart94wrx

Ok, Downpipe was split/leaking at flange (exhaust end) Took off said downpipe to get repaired. Put back on and plugged in sensor (plug under airbox) left lamda in pipe all the time. What else am I missing - is there another plug I've left off - dont think so at the moment. Wondering if the cats gone home, but don't know why it should?
Cheers for the input.
Mart.

Dark Blue Mark

I presume they did a weld repair? If the sensor was still screwed in the pipe, they may have buggered it from the heat when welding. Imagine that would be pretty hot!

If not, you may have to trust what its telling you and there may be a problem. Does the light appear when you start the car, or take a while to appear? If its instant it may be dead.

I would have put a decat on there anyway

MB

mart94wrx

DBM,
Many thanks for your input. The welding carried out was gas, rather than MIG, so no current passing through, knackering any sensors. The flange that needed welding is some way away from the sensor, and the Exhaust must get pretty hot anyway during normal use, so I'm hoping that it's still ok. My main system has no cat, so I need the one in the downpipe for the MOT's. It's been suggested in Lighting/Electrical, under my other thread, that unplugging the sensor originally, with the battery still connected, could have caused this hiccup, disconnecting the battery for fifteen minutes was the suggested remedy. I'm hoping that this could be the fix, but I'll reset the ECU using the wires under the steering column, rather than disconnecting the battery. What do you think.
Thanks again for your input - much appreciated. I,m just up the road from you by the way - New Milton.
Cheers,
Mart.

mart94wrx

MB, light is on when ignition comes on, then stays on immediately on startup. Hoping ECU reset works tomorrow, as previos post.
Mart.

RRH

I think I am fairly safe in saying that all this indicates is high temp in the d/p, hence the 'cat on fire'. Implications are limited to emissions as far as I am aware (and I'm prepared to be corrected) so if a reset doesn't sort it I'd unplug the sensor.

To re-iterate what DBM has said, it is not a Lambda sensor (which is in the exhaust headers) it is an EGT probe, sensing exhaust gas temp.

mart94wrx

RRH,
Many thanks. Have reset ECU, but fault still persists. Car runs fine, but would like the piece of mind of a clear dashboard. Any other checks that can be done on the EGT sensor? Would it need to be earthed to the downpipe - I can't remember any earthing straps or leads when dismantling, but could one be tucked away somewhere?

Cheers,
Mart.

RRH

from memory its a simple two wire affair. as I said I'd unplug it and throw it- possibly a rather cavalier attitude that will get me in trouble one day..... then your dash will be clear until something else breaks

any more technical than that I can't be; sorry mate.