Failed smog test...


Sep 4, 2004
ruined a perfectly good day by failing my smog test. i had the O/R pipe on for around 3 years, with the diablosport tune and mil. had the factory pipe installed, and retored the factory tune. i checked to see if there were any codes last night, and it said there was one for OBD test imcomplete. so then on the way to the smog station my engine light came on and the code description said my computer failed to communicate with the rear bank sensors. so i cleared the code(with the diablosport) and pulled into the smog station. i passed everything on the test, emmissions, gas cap, etc...but i failed because the "computer had no memory". the form says that i failed due to incomplete MIL/OBD test. but if i drive it long enough the chech engine light will come on and i'll fail again. any ideas? did i burn out my O2 sensors? thanks guys.
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Do you have MIL eliminators on the car? If so you need to pull them off....thats the problem. They wont work properly when you put cats back on.

If you dont, then yes your rear 02s are probably dead....I believe they are cheap so shouldnt be a big deal.
no i do NOT have MILs on the car. i used the internal option from the predator the deactivate the O2 sensors, so i didnt waste money buying MIL eliminators. i restored the computer to the factory settings. so clearing the codes, or erasing the "memory", is a no-no before a smog test?
ok, he said that when i bring it back he'll test it for free, just have to pay for certificate. but when i drive it like 30-40 miles it throws an engine code. if i test with that code present, will i still fail? or do you need the code number to check?
i dont remember the number of the code cuz i cleared it as soon as i saw it, but once i drive enough for the code to come up again ill let you kno. i remember the description being something like "rear bank error" or failure, something bad lol. i think its wierd cuz when i had the O/R pipe in i had to turn off the rear bank sensors to stop the engine light, so i figured that was the same as the MIL elim. but now the factory tune is installed and the factory pipe, so it must be a hardware malfunction, right?
The CEL will come on after every 'driving cycle' when it finds a problem. This means you can clear the codes, but after driving it a certain distance and parking it to cool down, the CEL will come on the next time you start the engine. As you learned, you need at least 1 'driving cycle' to pass emissions.

You'll have to get pull the and fix the problem. We have no idea what the problem is without knowing the exact code. If your rear O2 sensors are plugged in and the computer working, then it is likely you have bad sensors. To keep the sensors clean and working, the heater should be on and working, otherwise they'll foul. Seems like you may have killed the rear O2s by turning them and the heater for them off. Only a guess though.
which is bank 2 and sensor 2? what if it is unpluged? the techs at the ford dealer arent too bright from what i have experienced before...

i will try to get under it tomorrow but that is impossible unless i have a jack or ramps...
thanks for the help so far
pass side rear o2 most likely the one that is after the cat.

HO2S Signal Stuck Lean Bank 2 Sensor 2
DTC P0153, P0154, P0160, P1153, P2272, P2273, P2A03, or P2A04

HO2S Signal Stuck Rich Bank 2 Sensor 2
DTC P0153, P0154, P0160, P1153, P2272, P2273, P2A03, or P2A04

Swap 02's and see if the problem follows the 02 sensor. So take your pass side 02 post cat and switch it with driver side post 02.

If it is the 02, you will see the following:

HO2S Signal Stuck Lean Bank 1 Sensor 2
DTC P0133, P0134, P0140, P1133, P2270, P2271, P2A00, or P2A01

HO2S Signal Stuck Rich Bank 1 Sensor 2
DTC P0133, P0134, P0140, P1133, P2270, P2271, P2A00, or P2A01

then you go buy an 02
if you have the diablosport, you simply need to turn off the rear O2 sensors, clear the codes, then drive long enough for OBDII to do it's self check. I have gone through emissions twice having my rears turned off via the diablosport and never had an issue. Theres no need to replace the sensors if you have them turned off because they wont cause any red flags to the emissions tester.

what state are you in btw?

**you don't even need to return to the factory tune!!**
ok, i'll try turning them off and play around with the tunes, and if that doesnt work i will swap the O2's around. im in california, so we have pretty strict emissions here. i just dont want to be sent to the state test only, the guy i bought the car from removed two of the cats from the factory h-pipe and i really dont want to replace them lol. thanks for the help guys.
i unplugged the pass side rear O2 and i got a code saying the heater wasnt workin and the sensor was bad, along with the code i was originially getting, so i assemed i had a bad rear driver sensor. i replaced the sensor with a bosch, and the next day i got the same code. what can i do now? i'll try turning them off cuz i get a free test if i go back to this guy, but any ideas for the mean time?
You just have to turn off the rear sensors using your diablosport, their computer cant tell if you turn them off and it will keep your mil from coming on. After you turn them off drive for a couple days so the computer has memory.
ok, i thought i did that and i just had the engine light come on again, so i went on it again and made sure i put in for O2 configuration:OFF OBDII test:OFF and BID MIL:ON so that should solve the problem?
can some one here explaint for me what the **** is smog test ? wat happent if you fails ? and how much its cost ? I really want to know cause Im moving to cali very soon, and now I live where they dont give a **** about emission, you can get inspect sticker with windshield crack, and its cost $5 for the sticker.