*help* Dtc P0031 *help*

[Drifting02WRX]

so a few days ago i replaced my belts and belt tensioner. everything went well except for the check engine light i recieved afterwords. i finally got the time to pull the code and came up with this...

code: P0031 heater control circut low B1 S1

what i can gather as of now, is that its the upstream O2 sensor... is it just a coinsidence that it hapened RIGHT after i replaced my belts? r is thee something else i should look into?

if it helps its a 2002 wrx

[68sprintb]

the upstream AF sensor is the B1S1, so it looks like you clipped some wires for the heater circuit...

[Drifting02WRX]

so im thinking im going to just pick up a new up-stream O2 sensor... unless someone has something else to add... please?!?

[thejinxin206]

did the new 02 fix the cel?

[subarutech]

sounds to me like your off a tooth on your exhaust cam....i would pull the 2 side timing covers and see if the 8 marks on the 4 cam gears line up..ive seen such things happen before..you dont have to worry about the crank gear timing mark because it wouldnt throw that code..but im willing to bet your off a tooth on the exhaust cam.i would def check that before anything

[68sprintb]

sounds to me like your off a tooth on your exhaust cam....i would pull the 2 side timing covers and see if the 8 marks on the 4 cam gears line up..ive seen such things happen before..you dont have to worry about the crank gear timing mark because it wouldnt throw that code..but im willing to bet your off a tooth on the exhaust cam.i would def check that before anything

being off a tooth on an exhaust cam would throw an O2 heater code?

[subarutech]

yea it most certainly could..think about it if the exhuast valves arent opening in sync and open early unburned fuel is going to be poured into the exhuast..thustfore cause the o2 sensor to try and run more lean..the o2 is going to max out trying to compinsate once the ecu see's the o2 is maxed out and cannot compinsate it will throw a o2 code.after 3 fault detections... trust me i know what im talking about..im willing to bet you threw a o2 at it and the problem is still there???pull the 2 side timing covers line up the marks and see if they are on point.. get back to me let me know how you make out

[68sprintb]

but if the O2 was stuck low i'd think it would throw a P0171 bank 1 lean code , the P0031 is related to the O2 heater, not the actual O2 element...

[subarutech]

that would make sense,butu since when have subaru's made sense?ive seen that code before for timing being off..also so cam codes/lean codes/rich codes/ect...seeing as you just replaced your belt and there was no prob before and now there is id re-check your work before spending any money..only takes about 20 mins to check it..you dont have to pull the whole front apart just the 2 side covers