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Hi,

Looking for maybe some advice or something, i know or have read somewhere the Z18XE ECU's are common to failure?

Basically, the cars failed due to Emissions, here are some resaults

Last Year:
Fast Idle Test,
CO: < 0.20% Vol (Limits) - 0.00% Vol (Actual Value)
Natural Idle Test,
CO: < 0.30% Vol (Limits) - 0.00% Vol (Actual Value)

This Year:
Fast Idle Test,
CO: < 0.30% Vol (Limits) - 4.79% Vol (Actual Value)
Natural Idle Test,
CO: < 0.50% Vol (Limits) - 9.09% Vol (Actual Value)

So, from last years resaults to this year something major has happened. The ECU has been reporting the O2 Sensor1 Bank1 as faulty, it was replaced, it still persisted to say this was faulty, so i put another on... It still said it was faulty so i gave in and left Management light on for the past 6 months. AFM has also been replaced.

Today, i got those figures from the MOT. We tried putting a 1.5v Battery on +/- of the Lambda sensors connector (So basically disconnecting the lambda and putting a battery on +/-) figures were still the same.

We plugged in the scanner, the lambdas were reading 4.12v thats both PRE and POST. Reved the car a couple of times, the lambda readings went to 4.30v ... again PRE and POST.

Could it be possible my ECU is shot causing this issue being that it repeatedly reports a faulty sensor.

Have you reset the ECU since changing the sensors?

May not be the case on Vaux but i know if you leave the Neg Terminal disconected on the Fiats for 30 mins it resets the ECU back int ofactory mode, losing any memory of faults as it can adjust itself (Especially things like fueling) to compensate and then not go back to its original setting even though the initial problem has been fixed?

Like i say might not work on the Z18 engines or vaux for that matter

The ECU has been acting like this for 11 months, its been reset so many times i just gave up 6 months ago and didnt care.
Sensors were changed like 6 months ago.

When disconnect battery, doesnt work as its not the Service light, its the Management light it stores the Errors in memory.

Now i seem to have this problem!!!

sounds like cats not doin it's job

TBH i think its ECU, cat is fine.

ECU is a common failure

why would ecu cause excess co2 sorry if i'm being thick

Common fault, ECU has caused AFM's to go, ground them, its lambda's... works its way round. I think mines spiked.

if its been running rich for a long enough period of time it will trash the cat

when the modus shows lambda sensor fault and after replacing it the fault is still there and then replacing again and still broke its actually the temp sensor reading incorrectly meaning the air/fuel etc is worng and brings up a lambda sensor fault ?

dont think ive wrote that very well but nez/lee might understand what im trying to say !

i suggest using one of these;





jokes...

was gettin a bit technical so i thought i would lower the IQ level of the thread