Engine warning light caused by blowing exhaust..?

Charlton_King

Could this be?

There seems to be nothing wrong - oil and coolant at the correct levels etc - except for a slight blowing of the exhaust system. A small hole, I think.

Would this be enough to cause the engine warning light to show? No other warnings are illuminated.

Retrogamer

If it happened around the same time as the exhaust blow then it may very well be. The CO2 sensor may be picking up abnormal readings due to the leak.

If you get the blowing exhaust repaired and the light stays on, i'd get the codes read.

arcon5

Emissions light if between both sensors perhaps.

EML unlikely

colino

Very common for some systems to show a leak and put the light on for a tiny exhaust leak. A generic reader will probably show P0420.

Retrogamer

arcon5 wrote: »

Emissions light if between both sensors perhaps.

EML unlikely

I guess it depends on the car. Some older cars never had emissions lights and just threw up an EML instead

IamNotAllowedToUseMyName

The generic answer is that any known fault from the air intake through to the exhaust that might change the air flow could throw up a sensor problem and therefore a warning as the engine management system may not be able to reconcile the readings and adjust the ignition according to what is happening out there.

From my own experience, nearly flat batteries (barely able to start the car) can also throw out engine management warnings.

So, before going for potentially expensive diagnostic sessions with a garage, fix obvious problems first - especially as garages might mis-diagnose the problem if they disregard the existing faults (for example, I know I have had sensors replaced due to the flat battery problem - they charged the battery, didn't find the fault again, but changed the sensors as they are "known to fail").

Pennysmakepounds

Faulty EGR Valve can cause the light to come on.

Mine has been on for a year now with NO adverse effect on the car.

Liverlad67

Have a Toyota Corolla. The elm light was on car drove ok for months. Mot time car passed emmisions garage said blocked cat. Put bottle of cataclean in after few days light went out never came on since. Give it a try get a bottle from motor factors or halfords. Maybe lucky thought elm light on was fail but just advisory back in March. Apologies eml light not elm for pedants lol

jase1

colino wrote: »

Very common for some systems to show a leak and put the light on for a tiny exhaust leak. A generic reader will probably show P0420.

Yup, this happened with a Hyundai I had years ago. Low Calalytic Efficiency IIRC. Quite alarming until you know the cause.