04 C3 1.4 petrol

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citronut
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04 C3 1.4 petrol

Post by citronut »

customers had recovery out to her C3 last week and he fitted a new coil pack, and advised her to get the spark plugs replaced, which i did today, whilst she was here she pointed out the engine management light is on all the time but the car seems to be behaving its self,

i didnt have time today to stick my DIS LEXIA up it but will have it back in to do so,

is there any common fault that would bring this light on, or is it just the stored fault codes from the coil pack dieing causeing it to stay on,

regards malcolm
wheeler
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Post by wheeler »

It may well now have a knackered cat depending on how long it was missing for & you may well see a cat efficiency fault.
I would imagine that the breakdown guy would have cleared the original coil fault(s). Lexia it & take it from there.
citronut
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04 C3 1.4 petrol UPDATE

Post by citronut »

just an update now i have shuved the DIS LEXIA up it today,

it came up with permanent fault catalitic converter, ageing process,

i cleared the fault which put out the engine managment lamp, sent customer for a long drive and back,

pluged DIS LEXIA back in no faults found,

engine managment lamp still out,

so i wonder if it were the coil pack dieing a couple of weeks ago caused the lamp to light,

spoz time will tell

regards malcolm
wheeler
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Post by wheeler »

Did you read the live data from both oxygen sensors ? These will tell you if the cat is working or not. I reckon the light will come back on & the same fault code coming back within 500 miles.
citronut
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Post by citronut »

no i didnt read live data, but if it re/appears i will do,

regards malcolm
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Post by MikeT »

It's interesting the ECU's can determine the condition of the cat as I'd noticed something similar from Toby's Coupe and wondered how it's done.

I suspect it compares the pre and post cat sensors for similar readings, indicating the cat is not burning off the excess fuel/carbons. If I am correct, then it seems logical that a failed coil could also create the same "rich" readings from both sensors.

As Wheeler advises, it is possible the cat was permanently damaged by the excess fuel but so far so good if the fault hasn't been logged since the fix!
wheeler
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Post by wheeler »

MikeT wrote:It's interesting the ECU's can determine the condition of the cat as I'd noticed something similar from Toby's Coupe and wondered how it's done.

I suspect it compares the pre and post cat sensors for similar readings, indicating the cat is not burning off the excess fuel/carbons. If I am correct, then it seems logical that a failed coil could also create the same "rich" readings from both sensors.
The downstream oxygen sensors sole purpose is to monitor the efficiency of the cat, it has no effect on fueling/running. With the engine warm & the ECU in closed loop at idle the upstream sensor reading should continually fluctuate between 100-800 mV if everything is working correct, The downstream sensor should have a fairly constant reading (the actual value doesent matter). If the downstream sensor is doing the same as the upstream sensor then the cat is not working.
A failed ingnition coil can quite often flag up a rich mixture fault (not the cat ageing/efficiency fault)
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Post by danielsydney »

This little C3 is a smart one isnt it?
C3 Automatic.
"la vie est belle"
"c'est elle que J'aime"
www.tvcitroen.com
www.renaulttv.co.uk
www.pubstv.com
"arive en France"
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