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Discussion Starter · #1 ·
just bin for a short drive and my engine management light has come on, plugged my dreamscience unit in n it has come up with the code P0420

does anybody know what this is as im in south wales atm n need to drive back to yorkshire tonight for work in the morning and i am worried that it might decide to destroy my little fiestas engine :(

any help would be appreciated

Matt
 

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Do you have a Performance Exhaust System..?

It'll be ok to drive It to get you home then get It checked when your back.
 

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its all ok matt, your car is running rich (very rich as the ecu with std map will be adjusting the the new exhaust)

Dave
 

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I had this code last week, will be around 2 months after i put my exhaust on. Strange. I got it cleared and its not come back on again so all well
 

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The ECU measure in cycles, will atke about 50 miles or so to come on again. It's not a s serious DTC and you can drive like that.

@Pink, I've been living with P0172 for the last 3 years.
 

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I've had an Exhaust Fault Code for the last 4-5 Month's.

If I delete It,It just come's back on with-in a couple of Min's/Mile's.
it will do. mine came on within 30 seconds after i had a full system fitted. i had to go back for a map the next weekend
 

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But surely that MIL light being permanently on will mask any other potential issues your car may have? That's the only reason why I decided to rectify mine.
 

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I had this code last week, will be around 2 months after i put my exhaust on. Strange. I got it cleared and its not come back on again so all well
i put a decat pipe on and it took a week to put this code on and i drive all over but as of yet no probs
 

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A code reader picks up multiple codes, so if there are any new issues, it's easy enough to find.
Sure, but how will you know there are any other faults to check if the MIL light is permanently on? Unless you periodically plug your machine up to a fault reader to check, but what a hassle that is, just build a mil eliminator and be done with it.
 
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