Mot failure 😩

[1970Herbster]

Hey all, I’m hoping some one can shed some light on where to go with this, my daughters car, 2002 1.4 auto …..failed it’s last mot on emissions, took the week to try sort it, added some forte to the fuel and had a good run in it, it’s got 3 faults keep coming back after obd reset, I’ve cleaned out the MAP & EGR just for cause, since then I’ve ran the obd diagnostic emissions tester and it’s passed them all but keeps throwing the faults up. Any guidance on what to do next? I’m thinking of replacing the lambda sensor in the down pipe Cat, suppose I’m just hoping someone else has had something like this! I’m changing the oil and filter today, the plugs are pretty clean and set right. Fingers crossed one of you guys can help me sort this without too much trouble 🤞🏼

[mk2]

Try swapping the coolant sensor. It could just be running rich... They are a very very common sensor fail.

Diagnostics live data will tell you what the ECU is seeing.

But high CO readings are caused by too rich usually (all the oxygen drawn in by the engine has been used up by excess fuel and there's not enough O2 left for a clean burn). The average lambda reading is perfect, so that tells us that the O2 sensor is working fine.

Could be blow by gasses (block/divert pipe away from the intake for the test). Could be the O2 heater circuit if the sensor is reading 'slow'. Check fuses and relays?

Need more data...

 

[1970Herbster]

⬆️appreciate that 👍🏼 Will give it some checking over this afternoon, the fuses seems like a good shout as I’ve not even considered them 🤦🏼‍♂️ and there is a few individual fuses for the fault codes, if anything changes or I find anything further I’ll follow up on here 🙂