oxygen sensor heater signal & OVER FLO.

[supraman508]

On my 7mge i did a self diag.had to codes that came up.the first one was #21 that is oxygen sensor heater signal that only applys for turbo models.I don't have a turbo.The second code was #64-ect.Now the #21 somewhat deals with heater signal,since i don't have heat and don't have a 7MGTE engine,could that code somewhat have something to do with my 7M not having heat.HELP:bowdown: :bowdown: :bowdown: :bowdown: :bowdown: By the way,every time i drive a long distance lets say 100 miles it does'nt over-heat.but on the way back i have to check the overflo to see if it is full.And most of the time it is,so before i return back home after for that 100 mile hike,i have to syphon half of the antifreeze that is in the overflo back into the radiator.if i don't the needle will venture towards the 'H'.can somebody help please:bowdown: :bowdown: :bowdown: :bowdown: :bowdown:

 

[cuel]

lol. sorry, but o2 sensor heater has nothing to do with the heater in the cabin. Though it did make me laugh(sorry, but its funny). Code 21 is for the o2 sensor, code 27 is for the sub o2 sensor or sensor heater. You can check the o2 sensor according to the TSRM. http://cygnusx1.net/Supra/Library/TSRM/MK3/ It's in the EFI section, I believe. You might want to recheck your codes as well. There is no 64.

As far as the heater, could be the vsv, heater valve, plugged up or bypassed heater core, or a combination of them. Could also be a sign of improper coolant flow, due to degraded water pump impellers, stuck thermostat, partially clogged radiator, bad radiator cap, etc.
You need to have the radiator cap pressure tested. If it's not holding the correct pressure, the coolant will push past and fill the reservoir. You could replace it, they are pretty cheap. Just make sure the new one is rated for the exact same pressure(14 psi, iirc). Not that it's exactly what's wrong(could be any of the stuff listed above), but its a start.