Hello so I’ve been getting my cel on and it’s been throwing me a p0128 code I’ve been trying to figure this out but I can’t so far I’ve changed the MAF, Coolant sensor and the thermostat and it still comes on. I have a couple of things done to the RDX I have a K&N intake, rv6 catless, downpipe atlp exhaust, DW fuel injectors, dw fuel pump, rywire harness, hondata flashpro on a custom tune, running e85 please let me know if you guys can help!

 

the code is specific for a thermostat...what brand thermostat did you replace with?
also, there might be a blockage somewhere.

check for leaks

 

I replaced it with the OEM one I got it from the dealer

 

so, you're looking for a leak or perhaps a blockage of some sort.

 

I think I can eliminate the leak possibility because I’ve checked and it doesn’t seem like it’s leaking from anywhere so it could be a blockage. So should I get fuel system cleaner for ethanol and run it through?

 

or maybe the water pump is not doing its job

 

so should I change the water pump ?

 

instead of throwing parts at the car, you need to find the problem.

you have to check if there are leaks, if there is some sort of blockage, or if the water pump is working correctly.

throwing parts at the car is the wrong way of diagnosing something. and will just cost you lots of money in the end

 

i think ima try the ethanol cleaner since it’s just a few bucks and it doesn’t hurt to try and then I’ll go on from there to see what happens.

 

what would cleaning your fuel system do to find a coolant leak, blockage or bad water pump??????????

I would start by looking for leaks in the coolant system.
I would then take a sample of the coolant to see if there is any gunk in it.
if gunk in it, i would then take out the radiator and run water through it with a garden hose. inspect radiator for any signs of wear or damage.
I would then look at water pump for signs of leakage, corrosion or any bad noises.

checck upper and lower radiator hoses, are they both getting hot? or is one still cold?