i have a 2003 honda s2000 with 52k miles on it . today my check engine light came on on the way to school . on the way home i passed by the autozone and obd scan my car and i got 2 codes . i got p0172 and p0170 running to rich and fuel trim malfunction .i check the the fluids and everything looked fine . the engine looked fine and the car runs perfect . can it be a sensor ? well i reset the ecu by pulling the back up fuse out and the light came off and the car runs fine still but it seems like it has less acceleration then before . what caused the check engine light to come on ?can it be a sensor ? or did the ecu just had to be resetted ? i recently did the clutch my self and a allignment done at the dealer . thanks .

 

O2 sensor? Maybe the MAP Sensor.

Do you have a test pipe?

 

no i have no test pipe . my car is completely stock just has an aftermarket clutch disc and lightened flywheel . yea i was thinking 02 sensor or map sensor also. but wouldnt the light come back on after the reset if they were really damaged?

 

Not necessarily...

Sometimes it takes a little bit of driving for it to come back on. If you reset the ECU and then just turn the car on, it doesn't mean that the CEL will come back. Go drive around for 30 minutes and see if it comes back.

 

yea ive been driving and so far it hasnt came back on . but i got a feeling it is gona come back . cause why would the light come on in the first place if nothing was wrong

 

OBD2 systems are finnicky, they tend to throw codes a bit too often.

If the light doesn't come back on, I wouldn't worry about it.

 

Before the CEL comes on again, all related monitors need to have a status of "READY". For example, if the O2 sensor is malfunctioning, it will not throw a code for it until the ECU checks on its status and an actual check afterwards.