Check Engine light came on today with 4 codes.

**johnnyb** · 08-15-2011

My Fiance was driving home from work today when her check engine light came on. She took the car to auto zone and they pulled 4 codes from the car with 2 of them being the same code
p0137 twice
p0140
p0141
All of these say Heated oxygen sensor bank 1 sensor 2. So what do I need to fix and are the codes a big deal? Will her performance suffer? Thanks.

**dpzelenak** · 08-15-2011

http://www.grandprixforums.net/dtc.php
if there o2 codes then, you may just need to replace the o2 sensor

**johnnyb** · 08-15-2011

Thanks alot! Where is the sensor located? Is it easy to replace? What sensor do I need to buy?

**Slick2500** · 08-15-2011

Looks like the rear one, just jack up the car so you can get under it, the o2 sensor is in the ubend of the exhaust just before the resonator, get a 7/8" wrench if you dont have an o2 socket and wrench the old ****er out. Make sure you unhook it first though lol.

**johnnyb** · 08-15-2011

Thanks alot Slick!! Where is the best and cheapest place to buy? Do I tell autozone I need an o2 sensor?

**Slick2500** · 08-15-2011

Yeah autozone would be a good place if you want to get it locally, if you don't mind waiting I would check RockAuto Auto Parts but don't cheep out on the O2 sensor, I would try and get a Bosche or something. Rockauto has the same Bosche O2 sensor for ~$20 cheaper than Autozone.

**johnnyb** · 08-15-2011

Forgot to ask is that normal 4 codes for the same o2 sensor?

**Slick2500** · 08-15-2011

Yeah it has a code for different things with the o2 sensor and if the sensor goes bad all the codes will pop up.

**johnnyb** · 08-15-2011

Great thanks!

**hilldog23** · 08-24-2011

I am having a similar prolem with my 01 GTP. I swapped out my PCM for a reprogrammed PCM from 3800 performance two days ago. After driving it for about two minutes, the SES light came on. So, I took it to the dealer the next day to get the CASE learn done (was told that should clear the SES light. Two minutes after I leave there, the SES Light comes back on. So I took it to Autozone and got it scanned...came up wit a P0171 (aaFuel trim bak one condition) code, and a P0137 (aaH02S12 circuit condition (heated oxygen sensor bank aa1 sensor 2) code. Disconnected the battery for ten minutes, reconnected, the light was out. Was driving this morning for ten minutes, then the light came back on. Went back to Autozone, had the P0171 code again (and maybe the P0137 code too, but he said there was two 171 codes, and cleared them for me before I could confirm if the second code was in fact the 137 code). Drove for five minutes, then the SES light came back on. One thing I must mention is that I have no CAT on the car (didn't have one with the old PCM, but buddy of mine may have tweeked the last PCM when he put in down pipe with no CAT). Could the problem be my O2 sensor(s), or no CAT and reprogrammed PCM picking that up? Please help!

**dpzelenak** · 08-24-2011

you may just have to get the code tuned out of the pcm for the 02 sensor, but if your getting a heater ciruit code then that means the 02 sensor itself is bad,,have you tried hooking the other pcm up and seeing if the codes come back

**hilldog23** · 08-24-2011

I can't hook the other one back up because I already sent it back. Sorry about multiple threads, but I replied to a couple before I actually figured out how to create a new one.

**dpzelenak** · 08-25-2011

do you know if the codes are suppost to be out of that pcm, if your not running a cat then you souldnt be getting anything for the rear 02 sensor when the pcm is tuned for it

**hilldog23** · 08-26-2011

This PCM wasn't tuned for no CAT (I think my buddy tweaked my old PCM by removing the codes from it).

**dpzelenak** · 08-27-2011

it would be a good idea to get it tuned for a no cat, are one of the codes p0420?...cause thats for the cat itself..do you even have a rear 02 hooked up?..cause if not that could be causing the heater ciruit code..you could run a dummy 02 making everything is working fine...i think there like 30-50 bucks or so

**hilldog23** · 08-28-2011

Had the car jacked up by a exhaust shop yesterday. Has an rear O2 sensor tucked away (cut no CAT). Throwing codes P0171, P0137 and P1133. Old PCM definitely had O2 codes removed when they installed the downpipe and removed the CAT (same time). Ordered a rear O2 Emulator yesterday (is that what you mean by dummy O2?).

**hilldog23** · 08-28-2011

Sorry, meant 'but' no CAT. All of these codes didn't come up until I replaced my old reprogrammed PCM for the current reprogrammed one from 3800 Performance. Says the O2 Emulator will eliminate the SES code associated with removing or unplugging your post-cat (rear) O2 sensor...and it plugs directly in to the stock harness. Hope this works. Thanks guys.