dbullen

iTrader: (3)

Getting check engine with above code (1990 LS400). Replaced O2 sensor on drivers side with Lexus OE sensor. Still getting the code. It also sounds like there is a slight leak somewhere in the exaust near the manifold on the same side. Would this cause the Error 21? or is their something else I should look for?

PureDrifter

iTrader: (10)

i havent checked but provided that code 21 isnt a o2 sensor circuit or heater circuit code, and is a general inefficiency code, then yes, it could be very easily cause by an exhaust leak.

dbullen

iTrader: (3)

21 - Main oxygen sensor signal (on left bank)

python

iTrader: (4)

an exhaust leak will cause the 02 to think theres a lean problem...

qewani1

as per this post
http://us.lexusownersclub.com/forums...hl=error++code
error 21 is for "Solar Sensor Circuit"

PureDrifter

iTrader: (10)

this only applies when you're diagnosing the A/C, and this code comes up on the Climate Control LCD.

odd question but have you ohmed out the TPS? it seems that the generic OBDI code 21 is a TPS code, but lexls has it listed as a bank 1 no.1 O2 sensor?