- Thread starter steveo3002
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Might be worth disconnecting the battery to reset adaptives, maybe you have an option of this on the scantool.
A p0420 fault should not reappear after a few miles driving , it requires id guess in region of 100miles to bring up the fault.
TBH if the sensor was faulty usually it would bring up a different code, I dont think ive ever seen a p0420 being anything other than
failed cat.
Its also possible the sensor voltage of 1.2v is substituted by the ecu once a p0420 has been been triggered.
A p0420 fault should not reappear after a few miles driving , it requires id guess in region of 100miles to bring up the fault.
TBH if the sensor was faulty usually it would bring up a different code, I dont think ive ever seen a p0420 being anything other than
failed cat.
Its also possible the sensor voltage of 1.2v is substituted by the ecu once a p0420 has been been triggered.
steveo3002
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hovering around 0.1 v or so
Have a watch of Scannerdanner on youtube, he is in the USA but is a lecturer in automotive fault finding. Has loads of great videos on confirming if an O2 sensor is at fault or not.
He works through lots of problem cars with the ethos of "don't be a parts swapper" in other words only swap a part you have confirmed is faulty. He is really interesting to watch and explains things really well.
He works through lots of problem cars with the ethos of "don't be a parts swapper" in other words only swap a part you have confirmed is faulty. He is really interesting to watch and explains things really well.
steveo3002
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steveo3002
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right heard back from ford £250 for theirs vs £40 for not in a ford box
i do understand nasty fake ebay rubbish wont work , but why shouldnt a genuine denso /bosch etc work....they give out 0-1v signal right? if its doing that why would the one in the ford box work great and the other correct spec one not
not trying to start an argument , but theyre not really super high tech are they ? signal is a signal ?
i do understand nasty fake ebay rubbish wont work , but why shouldnt a genuine denso /bosch etc work....they give out 0-1v signal right? if its doing that why would the one in the ford box work great and the other correct spec one not
not trying to start an argument , but theyre not really super high tech are they ? signal is a signal ?
steveo3002
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dont know anywhere id trust , pretty much £90 diag fee and yer its your ecu innit type places around here
will press on a bit longer ...my live data isnt any different to theirs
will press on a bit longer ...my live data isnt any different to theirs
qwakers
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+1 you need a scope to diagnose that correctly.
take a look at this guys videos. he's probably fixed your exact issue in one of his vids.
there are one or two vids of his (the Maserati for example) where he overcomplicates it from the start where basic checks (of the cam timing in that case) would have had him to the answer much faster... but for the most part his work is very interesting.
take a look at this guys videos. he's probably fixed your exact issue in one of his vids.
there are one or two vids of his (the Maserati for example) where he overcomplicates it from the start where basic checks (of the cam timing in that case) would have had him to the answer much faster... but for the most part his work is very interesting.
steveo3002
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back probe the connector with a pin or something ?
analogue meter , one side earthed other into the signal ? see if it matches what live data says ?
Chippie
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Your approach seems reasonable, however, if the ecu input for the sensor was damaged in some way, it could affect the reading the sensor is trying to provide…hence why I said jury rig a supply to the sensor and measure what comes out….(makes sure you measure the supply going to the sensor first…and match it, don’t just stick 12v on it)
If the output voltage is around the figures quoted within this thread, then your meter on the 200mV range should suffice, or switch up to the next range….
steveo3002
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right thanks for the above...will have a think if im to bench testing the sensor
called in the mot center and he tested the emmisions , it passed so cat is fine and the pressure is off as i can get an mot now
still want it fixed
heres a snap of the output just now...one random spike up to normal reading ,kinda says damaged wiring or ecu i dunno
will be at least this weekend before i can get a meter on it
called in the mot center and he tested the emmisions , it passed so cat is fine and the pressure is off as i can get an mot now
still want it fixed
heres a snap of the output just now...one random spike up to normal reading ,kinda says damaged wiring or ecu i dunno
will be at least this weekend before i can get a meter on it
mtt.tr
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I love this, will certainly be using this phrase in the future
steveo3002
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are you saying bench test it ? all i have is spare battery /charger , could i waft a gas torch under to see if the reading moves ?
Oxygen sensors generate their own voltage once warmed up, which is why they have a heater, so they work sooner. Testing on the car should be first, back probe and take a reading, you can check the heater is getting power first then signal.
The heater would normally be the 2 wires that are the same colour and the sensor signal and ground the other 2.
