Diagnostic Codes

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New Member
Boynton Beach FL USA
I have a 92 SC400.Can't get rid of check engine light.(code 52,#1 knock sensor). Replaced both knock sensors, replaced KS connectors, ohmed out wiring, no problem found.Only thing left is ECU.Is there anything I overlooked?Looking for answers.


Active Member
I had a supra 2j with same issue
what I did was swap the pins for the two knock sensor
on the ecu plug over. so knk 1 swap with knk 2
if the code stays the same like 52 it's an ecu issue
so I'm chasing a 2j ecu


New Member
Gold Coast
I had a similar problem with a JZZ30, 1J. would randomly throw code 52. So I just split the knk 2 signal, and ran than into both pins of the ecu. It worked for a while, then I noticed the same fault coming up at a later date, but without the huge ignition retard whilst driving. Anyway, replaced all the caps in the ecu, and all has been good so far.

Just on a side note, does anyone know if it possible to retrieve codes via the rectangular diagnostics box on 1U ? it doesn't have the oval plug after the engine conversion. It has Pin 'W', which I believe is the CEL wire, but voltage when in diag mode seems very low to trigger a check light.



New Member
pleasant point
fault code 56

well i have googled the world and read till my eyes hurt . i have a ucf 20 that i have fitted into my toyota surf and have this annoying code 56 as soon as the key is on . what i have found is that it might be the missing hydraulic oil level sensor missing and i did read one post that said its a blue wire in one plug but its not that good of a description as i have found this wire ( i think ) and grounded it but still have the fault my ECU number is 89661-50240 info i have on this is thatits a 1996 ucf20 out of a toyota celsior . i have most parts wired and working well but this code seems to be a hard one os my question to the group is have i wired it wrong or is there something that i have missed when i wired the engine .and if i was any good at this inter web thing i would put up some picks of my work maybe some one can help me there aswell ..... thanks for listening