sorry i dont know if this is the right place to put this but we just took the monte carlo in for emissions and failed because it has a check engine light
and here are the codes i have this one was in current DTC....P0420 then these were under all DTC's B3128 P0128 P0463 C1245 U1016
weve had problems with this car it is my 03 with the 3.8 i think? its the SS edition no supercharger nothing aftermarket on it we have a month to fix it
any help to look for would be great!!!!

 

do you know what any of the codes refer to? if not check this thread out and see if it helps..

Sticky: GM OBD II Trouble Code List
RocknSS04

 

P0128 is coolant thermostat
P0420 Catalyst System Low Efficiency
P0463 Fuel Level Sensor Circuit High Voltage
U1016 Loss of Class 2 Communication with VCM
C1245 ABS Outlet Valve Coil LR Circuit Short To Ground
B3128 = LF Door Only, Unlock Circuit High (BCM)

 

if nobody here can help, try doing a google search. sorry, wish I had more info for you.

 

bump!!!!!!!!!!!!!

 

did you do a search? this is what I came up with when I did a search, goodluck, see link below...

http://www.obd-codes.com/

 

OK i updated the list now i need help how to fix them!

 

i just searched them! thanks for your help..wanna know how to fix them

 

Go to a gm daler and buy an oe temp sensor they are the best. As for the P0420 that is usually catalyst efficiency code, means cats not working good enough. Sometimes a post cat oxygen sensor can cause this by reading low voltages usually around .250 acv and .050 acv a scanner with o2 sensor data could help you here but the unfourtunate reality is the cat will be bad. Your car probably has around 90, 000 miles or more on it. The only codes that matter for emissions testing should be P codes the other ones won't turn on the engine light. C code could be the abs pump unit, ask a garage if they have a pressure brake bleeder and have them flush out all your old fluid. While they are doing that they should run the pump motors and cycle the solenoids in the abs unit. I've done this myself to keep certain abs codes from comng back. U1016 can be caused by just dissconecting a module with the battery connected. If there has been any work done in the past 50 key cycles those codes will remain in the bcm. The B code drivers door thing maybe you had a new window regulator installed recently?

 

P0128 is coolant thermostat: Start by checking the fan fuses to make sure they are good. If they are good, change the thermostat and flush the cooling system. If you still have the dexcool the car originally came with, it's probably too weak to do it's job.

P0420 Catalyst System Low Efficiency: Have your catalytic converter check for blockage/failure, and your O2 sensor to make sure it's not faulty.

P0463 Fuel Level Sensor Circuit High Voltage: Is your fuel gauge bad? It could be a bad/sticking float in the tank or a BCM going bad. You should have a dealer take a look.

U1016 Loss of Class 2 Communication with VCM: Possible BCM going bad? Dealer time my friend.

C1245 ABS Outlet Valve Coil LR Circuit Short To Ground: You should check your left rear hub for wear and, if defective, replace it.

B3128 = LF Door Only, Unlock Circuit High (BCM): ???? Maybe the BCM needs reprogramming? You should have the stealership check the BCM. I'm sure one of the certified mechanics on the forum will come up with something else that i may have miss. Good luck bud!